Technical Advice: Rebuild and remanufacture CV Axle 3

[tarekzad]

I was looking for a technical expert in the field of CV Axle rebuild for Rppza and Tripod Joints.

we are talking here about repair the damaged axle by welding makeup, grinding and r-assemble.

we have an automotive workshop in Jordan - Amman city specialized in rebuilding used automotive spare parts, and we are seriously planning to expand our service of remanufacturing to CV Joint Axle. in this regard, we are looking for a technical expert having solid experience in repairing different and wide spectrum range of CV joint like Plunging joints & Plunging tripod joints

Repezza Joint
Welding makeup for Outer Race
Welding makeup for Inner Race
Replacing the Ball Bearing. ( after evaluating if the shape is still workable or not [ i.e. due to metal plastic deformation or out of roundenss] )
Welding Bearing Cage


Tripod Joint

Welding makeup for Joint Outer Race/outer Ring
Evaluation of the workability for Joint Spider
Welding makeup for Ball case
Replacing Needle Bearing
Replacing Bearing


Please advise your experience with thanks in advance

 

[RRiver]

@tarekzad,

I'm sorry but I can't help you with actual questions but I am curious about your question. As much as I abhor Chinese repair parts, most CV axles can be had for less than $100 US and many less than $50 US. Even less in Jordan from my experience. Just based on your experience identified by your question what do you hope to gain from repairing CV axles? I'm just guessing but wouldn't mass production repair be required to make it profitable? How are you set up to ensure quality control? Honestly, I'd choose the Chinese parts over a repair from the corner job shop without a lot more information about your plans. For example, "welding" has a lot of different meanings to different people. What are your referring to? Doing what's necessary to get something back on the road is a far cry from an actual repair.

Hate to see something go unanswered.

 

[tarekzad]

Dear R River

Thanks for expressing interest in my post.

Indeed the Price as Fob or Ex-stock is 50 USD, however, with governmental levies, the price is doubled, and with retailing profit, it almost tripled.

CV Joint cost at the market might be 100 to 120 USD, not when CV joint fails, it need ball replacement, we have 6 balls, and balls with extreme estimation won't cost more than 1 USD, welding and reaping for the scoring metal, adding grease, replacing BOOT with clamp is not exceeding 7 to 10 USD.

Indeed the business like any business will not be viable either feasible without the scale of economy and mass production.

Jordan market is dominated by few makers, mode and Years, when I say dominated I can tell you that 5 to 6 Carmaker is dominating more than 50% of the 1.6 Million Vehicle. this is leading us to envisage the a huge amount of scrap will be identical, and the learning curve will be high.

By market survey, we found that the age of CV joint is Jordan has ironically reduced because owners are not reckoned that CV boot is broken, and grease went out and replaced by mud. the are somehow extremely stubborn to keep driving the car while CV axle is loudly clicking, then the driver lost his control and causes his car damage with 1,000 USD due to ball joint or CV joint breakage.

Jordan vehicle owner purchasing power is dropped in the last years, and start maneuvering around the v=brand new cost of CV joint by buying used Axle, which is a temporary solution for such a situation.

Jordan road is so mountainous, with colossal of potholes and dents. Curves are so sharps and mixed with high slope sue to the mountainous terrain.

we are following a recycling business says not every scrap is crap.

 

[Tmoose]

I applaud your effort to find a business niche.
On the other hand, your description of the CV joint repair process makes me think that the durability of your product may be in danger.

I have no first hand knowledge of CV joint construction.

SAE "Advances in Engineering Series No 7 - Universal Joint and driveshaft manual" describes the inner and outer housing material thusly - low carbon alloy steel forging, carburized to an adequate case depth and surface hardened to HRC 60 minimum. The spherical "race" surfaces are finish ground. Reference is made to an appendix that has calculations for required case depth based on loading.

The contact surfaces in ball and roller bearings in all but the lightest service can be subject to deep fatigue inducing "Hertzian" stresses. Thus rollers, balls and races are made of VERY clean, deep hardening steels, HRC 60-ish, and magnificently and precisely finished.

I fear any shop welding, indeed any welding done by man or woman or robot will deposit material vastly inferior to the original in many important ways.

I too wondered how a CV joint is rebuilt. My hunch is grinding the worn "race" surfaces and fitting oversized balls/rollers. This is how big expensive roller bearings are reconditioned.

https://www.timken.com/wp-content/u...-Extend-Bearing-Life-For-Heavy-Industries.pdf

 

[RRiver]

Tarekzad,

I have to agree with Tmoose about this.

You lost me in your description of what you believe is needed. Here is an example of CV axle along with what's included for a 2005 Ford Taurus that is less than $35 US:

https://www.rockauto.com/en/moreinfo.php?pk=3857823&cc=1430709&jsn=635

First off, from what you describe it sounds like the major problem you're seeing in Jordan is poor maintenance, axle protection that isn't surviving your road conditions and additional costs that really have nothing to do with CV axle failure but are related costs. Reminds of warranties that state "labor not included." A $4 part will gladly be replaced for free when installation labor is $100. Accountants will probably never stop laughing over that deal!

I'm curious, instead of repairing CV axles have you considered designs and materials that would extend the life of the axle protection? Something like a secondary boot impregnating a metal fabric mesh? You did ask about rubber so I assume it is something you are capable of molding?

I had no idea about the SAE standards Tmoose identified but in my opinion they sound expensive unless your remanufacturing volume well exceeded the damaged axles from such a small pool of vehicles with damaged axles.

You also stated the majority of vehicles come from 5 manufacturers. That has to drastically define where the work and income is at. Have you considered pursuing bulk purchases of CV axles concentrating on where the work is at covering those manufacturers and the predominant vehicle models in Jordan? Heck, you could even warranty the parts also and your accountants can laugh at the labor charges and additional vehicle damage repairs.

Considering 1.6 million vehicles as you say, if you replaced an axle on 10% of your potential customers every year (which is outlandish to even consider) it would be a long time before you saw a profit if ever. Manufacturing is a plant, equipment, overhead and labor extensive\intensive business to pursue in the automotive parts business your considering. I can't even imagine what a center or centerless production grinder, production spline cutter, the required production welding machine, carburizing machine (or what ever it's called), production oven(s), the required QC equipment for the required SAE, ISO or whatever standards are required for the necessary certifications for axles, a skilled machining labor force, etc., etc., etc. Again, somebody at a bench with a torch, mig or tig welder and someone at a Bridgeport is not an axle repair. That's just doing what's necessary to get a vehicle on the road until it can be repaired. It just might be more profitable to get a couple of trucks and drivers to go out and track down all the failed axles you mention and recycle them as scrap. I don't mean to be harsh but that could be true.

Again I agree with Tmoose, I applaud your initiative but I know next to nothing about automotive parts production and I'm questioning your plans. I know there are members of this forum that know this business and they've remained silent. Sometimes silence says a lot. If you're dead serious about this the best I can say is find someone experienced with developing business plans for automotive parts production and start there. I honestly wish you all the best and success Tarekzad.

 

[tarekzad]

Dear RRiver

I think we have to segment the reply to parts a and to avoid getting lost inside the reply body, we have to tackle each point separately, so the below will be the feedback
I have numbered the point to make it easy for quote and citation in the future

Point #1: I have to agree with Tmoose about this.
Reply: noted
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Point #2: You lost me in your description of what you believe is needed. Here is an example of CV axle along with what's included for a 2005 Ford Taurus that is less than $35 US:

https://www.rockauto.com/en/moreinfo.php?pk=385782...

Reply: I have stated that 35 USD is online price is the state, and I'm intensively using rockauot website. however this price can easy be converted to 120 JOD , JOD = 0.71 USD, so somehow you can find it on the shelf of dealer sold at 150 USD.[/color]
*****************************************

Point #3: First off, from what you describe it sounds like the major problem you're seeing in Jordan is poor maintenance, axle protection that isn't surviving your road conditions, and additional costs that really have nothing to do with CV axle failure but are related costs. Reminds of warranties that state "labor not included." A $4 part will gladly be replaced for free when installation labor is $100. Accountants will probably never stop laughing over that deal!

Reply: Road quality and topography is the main issue, combined with you have stated above.the 4 USD is the labor cost for one hour when you pay it for your staff, in Jordan non-educated labor is earning 600 to 700 USD per 208 Hrs per month. however, when you are stepping in Garage owner shop, the fees will never be estimated or given by the stopwatch. they will charge 20 JOD which is around 27 USD , I was referring to the mass production and salary rate with my figure 4 USD.
****************************************

Point #4: I'm curious, instead of repairing CV axles have you considered designs and materials that would extend the life of the axle protection? Something like a secondary boot impregnating a metal fabric mesh? You did ask about rubber so I assume it is something you are capable of molding?

Reply: The vehicle will step in the garage on a recovery truck after big failure in the street or when the owner fed up with clicking noise. I will search for Boot impregnating with metal fabric mesh, but I think the boot will lose a salient portion of it is elasticity.

***********************************
Point #5: I had no idea about the SAE standards Tmoose identified but in my opinion they sound expensive unless your remanufacturing volume well exceeded the damaged axles from such a small pool of vehicles with damaged axles.
Reply: I will do my best to explore the SAE Standards, the business of CV repair already existing but in the primitive level of skills. there is a queue of shafts stands on. I will arrange in the future to send you some footage of the process and shops even.
*****************************

Point #6: You also stated the majority of vehicles come from 5 manufacturers. That has to drastically define where the work and income are at. Have you considered pursuing bulk purchases of CV axles concentrating on where the work is at covering those manufacturers and the predominant vehicle models in Jordan? Heck, you could even warranty the parts also and your accountants can laugh at the labor charges and additional vehicle damage repairs.

Reply: the journey of soliciting the price of CV joints and CV axle full assembly started already with chines, Korean, Indian and Turkish factories, initially, there was some hindrance of fetching out the OEM #, but I came over this point.
Indeed Korean and Japanese vehicles dominating the market, see the below list

A: Ford Fusion 2006-2017 /Escape Hybrid 2005- 2017
B: Hyundai Accent 2000-2017 / Sonata 2000-2017 / Elantra 2000-2017/ Tucson 2005-2017 / Ioniq 2017-2019
C: Kia Optima 2001-2017 / Sephia 2000-2001/ Sportage 2000-2016 / Rio 2001-2017 / Spectra 2002-2009 / Soul 2010-2017/ Sorento 2003-2017/ Niro 2017-2018.
D: Mazda CX-5 2007-2017 / Mazda 6 2003-2017 / Mazda 3 2012-2017
E: Mitsubishi Lancer 2002-2017/ Mirage 2000-2017
F: Nissan Leaf 2011-2017 / Sunny or Sentra 2000-2017
G: Toyota Camry Gas & Hybrid 2000-2017/ Corolla 2000-2018/ Prius 2001-2017 Prius C 2011-2017/ Prius Prime 2011-2017/ Yaris 2007-2017
H: Honda Civic 2000-2017/ Accord 2000-2017

Some of those manufactures is using soft metal, cheap boots, to reduce the cost of parts.
By talking about warranty, the Asian MFG will never provide a warranty in any shape, in return as a dealer you can’t provide.
Point #7: Considering 1.6 million vehicles as you say, if you replaced an axle on 10% of your potential customers every year (which is outlandish to even consider) it would be a long time before you saw a profit if ever. Manufacturing is a plant, equipment, overhead and labor extensive\intensive business to pursue in the automotive parts business your considering. I can't even imagine what a center or centerless production grinder, production spline cutter, the required production welding machine, carburizing machine (or whatever it's called), production oven(s), the required QC equipment for the required SAE, ISO or whatever standards are required for the necessary certifications for axles, a skilled machining labor force, etc., etc., etc. Again, somebody at a bench with a torch, mig or tig welder and someone at a Bridgeport is not an axle repair. That's just doing what's necessary to get a vehicle on the road until it can be repaired. It just might be more profitable to get a couple of trucks and drivers to go out and track down all the failed axles you mention and recycle them as scrap. I don't mean to be harsh but that could be true.

Reply: the 1.7 mil. Vehicles is the overall ocean of vehicles, there are heavy vehicles, motorcycle, special vehicle, logistic vehicles, I have a long model for funneling the market.
There will be no spline cutting. We will treat the joint, not the axle.
carburizing machine = heat treatment oven
QC testing station is quite simple. Motor and clamps.
Tools and welding machine is not that costly since we are not talking of 400 Amp welding machine.
Recycling of CV Joint damaged is what is going on currently, the scrap price is 0.10 USD/Kg, so joint scrap sold at less than 1 USD. The business idea is not based on fixing standing on customers CV joint [ fixing the cars arrived to shop], the model is about collecting what has been considered scape and we see it not crap.
“I don't mean to be harsh but that could be true” I will never feel offended by your comments, it is so positive and health criticisms.
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Point #8: Again I agree with Tmoose, I applaud your initiative but I know next to nothing about automotive parts production and I'm questioning your plans. I know there are members of this forum that know this business and they've remained silent. Sometimes silence says a lot. If you're dead serious about this the best I can say is find someone experienced with developing business plans for automotive parts production and start there. I honestly wish you all the best and success Tarekzad.
Reply: all of the encouragement from you and from Tmoose is really appreciated.
By talking about the business plan, I’m owning a boutique business consulting firm, so feasibility studies and business plan are our daily bread and butter, if there is a chance to have an online meeting, I can present my business plan and feasibility study, with excel file, have 3 MB data file and 60 MB MS presentation file. I’m not pretending Owning the success, but success has a key and I own a couple of them.
The business model has certain tractions, which makes it viable is a specific geographical area more than others.
My company name is ZAD consult, located in UAE – Abu Dhabi city [ capital of UAE ].
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I know that writing such a reply took much time from you, as well as the reading my reply will take, but it will be a good business and technical brainstorming.

Have a good day RRiver & Tmoose

 

[swall]

Repairing CV joint outer races is not economically feasible. The tracks on outers are precision ground with special grinders dedicated to the task. The heat treatment is predominantly induction hardening (SAE 1050 steel). There are some SAE 5120 outers that are carburized but induction hardening predominates. Inners are SAE 5120 steel, carburized. The starting form of both outer races and inner races is a forging. Hard to replicate on a small scale of production.

 

[tarekzad]

Dear Swall

Thanks for your feedback.

I will check the data you have provided and revert shortly, however, I believe from your feedback that you have solid experience in this field as a producer for CV joint, since there a scarcity of documents and data on the internet is talking about the CV joint races and element material.

Currently, there are primitive shops welding the cracked nd broken cage, replacing the deformed balls, welding using inappropriate welding electrode, grinding using pencil grinder without any measurement for the surface roughness and integrity. simply these shops are ruled and managed by low educated technicians, just to put you on the atmosphere of their knowledge, they have no idea about the hardening, heat treatment, annealing process.

So obviously what we are about as a business model is to modernize this process and add the engineering strong flavor on it.

I will never be prejudice and biased to say it is 100% viable and feasible, that it is why I'm hearing all of the technical feedback such that one comes out from you and other gentlemen above.

If I am moderately convinced that the repair process will be fruitless, then I will never go with a business that generating and selling false hope and false repair to the customer, even though customer knowledge is below the ability to discover that hoax.


I will be more interested to know about the groove grinding precision. I have roamed all the internet and never find a scholar or technical papers in this field.

Please read what I wrote about the market situation in Jordan.

what is making it feasible is

1- high customs and levies.
2- VAT Tax
3- Mass Prduction


Already the customer is buying used axle and CV joint from car scrap part dealers. the high price of new one pushed the customer to be gamblers and accept the idea of buying used part dismantled from total loss and write off cars.

Thanks again for your valuable feedback. and please feel free to add your next comments. I will be all ears for that one.

Tarek

 

[RRiver]

Tarek,

It's late here but quickly:

I can't speak for what may or may not be acceptable in Jordan but here, what you are researching doing would not be consider rebuilding or repairing. What you're talking about doing here is what a small shop mechanic does so a car owner can get home and get a proper fix. And, a reputable mechanic would take in to consideration what the job is and how far is home. This is the kind of thing that can ruin reputations.

Let me revisit an earlier suggestion. When I mentioned a "secondary boot" I wasn't referring to a replacement. I was thinking of a "secondary boot" that's as universal as possible to limit the number of required boots. This secondary boot would go over the original boot for additional protection and designed to limit any possible interference with the original. This is why you can look at a rubberized metal\fabric composite. This would also allow you to target every car and not just the biggest sellers. Take a look at some of the off road dealers here and you'll see a lot of aftermarket parts available with the sole purpose of protecting the OEM or better parts. Something that's obviously not available in Jordan.

 

[BrianPetersen]

I will be more interested to know about the groove grinding precision. I have roamed all the internet and never find a scholar or technical papers in this field.

That's because it's done using highly specialised equipment which is proprietary to the manufacturers of these parts.

In order to be able to produce those parts and sell them for (let's say) 100 euro on this multi-million-euro production line, the parts have to be produced in enormous quantities. It's practically certain that the good-quality aftermarket parts - leave cheap short-lived replacement parts out of this discussion, please! - are coming from exactly the same production line that produces the parts for the original vehicle.

You are NEVER going to be able to produce original-equipment-manufacturer-quality replacement parts, for that price, on anything but the original production equipment, and in a huge production volume that the production line is designed for!

You are going to find that the CV joints for a Renault, and the CV joints for a Fiat, and the CV joints for an Opel, are very similar and have very similar (if not identical!) bits and pieces inside, even though the "easy parts" - the length and diameter of the shaft, the arrangement of the splines, circlip grooves and bolt threads, etc - may differ between them.

And that's how the specialty manufacturers are still able to get you replacement shafts for a 25 year old car which is long since out of production: they are using the "tricky parts" - the ball cage, the balls themselves, etc - from something that is in current production - they may not have even changed!! - and attaching them as needed to the "easy parts" that connect them to each other and to the vehicle - the shafts, the splines, etc.

In order to be able to do this ... you need to have access to those specialty bits and pieces that are coming from that highly specialised machining, heat treating, and grinding equipment.

I cannot help with this. I have no connection to manufacturers of CV joints. Other parts, but not those. But the same concept is at work. I know for a fact that the good quality aftermarket timing belt tensioners for a VW 4 cylinder diesel engine come off the exact same line as the parts destined for the VW engine assembly plant and for VW dealers. If you buy a cheap copy, you are taking your chances ...

N.B. I have never had to change a CV shaft on any vehicle I have ever owned, and I've taken a couple of front wheel drive VW cars past 400,000 km.

 

[gruntguru]

I recall about 25 years ago a company setting up in Sydney, Australia to recondition CV joints. They were machining a small amount from the races and fitting over-size balls. The milling was done on the same equipment as used in OE manufacture of CV joints. Obviously only feasible for worn joints - not chipped or pitted.

I must have disassembled dozens of CV joints in the days when I was a Mini enthusiast. You could get some more life out of a noisy joint with new balls, grease and boots. Swapping the joint to the other side of the car (to load the opposite side of the races) often helped too. CV's are much more durable these days.

CV joint Machining (outer race) Link
Sharpening a CVJ cutter. Link


je suis charlie

 

[BrianPetersen]

Cool videos. Special purpose multi-axis CNC grinding machine ... and there will be one for the outside race (the one shown), one for the inner race, one for the ball cage, plus the additional special equipment for cutting/sharpening the tooling. And the rough-machining equipment, and the heat treating line, and the equipment for making the precision balls. And that's just the outer Rzeppa joint. Then there's the inner joint, which is usually a quite different design, but which itself needs equipment of this sort. Not cheap!

 

[tarekzad]

Dear BrainPetersen

the plan is to repair a limited segment of vehicles, there are some countries in the middle east where the market of vehicles is dominated by key players. like Hyundai and Kia.
I do agree with you that varieties of Rzeppa joint are a challenge but since the CV Axle is an element not manufactured by vehicle OEM, then it supplied by aftermarket manufacturers, and the design of CV axle is depending on the horsepower of the engine, and most of these cars dominating the market have 1.3 to 2.0 Liter engine, then the varieties will be limited in certain CV Axle with spindle diameter ranging between 15 to 25 mm diameter. this fact5 will make the repair much easier.

the business idea is not based on manufacturing from scratch, it is based on repairing the CV Inner, outer Race, and mainly in Rzappa part not on the tripod side. then we don't need for highly automated grinding machine for the full automation process. pencil grinder, on another hand, a small heat treatment oven will be adequate to accommodate 15 to 20 joints per batch.

 

[BrianPetersen]

"Pencil grinder"?

Is that what I would call a "die grinder" - a hand-held power tool?

This has no chance of achieving the dimensions and tolerances and surface finish required for the completed repaired part to have acceptable durability. It would be an emergency "get-you-home" at best.

You don't need the automated pick-and-place and conveyor-fed system of that special-purpose CNC grinder ... but you do need the CNC part of it and the special machine to shape the tooling, in order to get the part to the right tolerances and surface finish. And the know-how to use it, which I certainly don't have.

My record for shortest life ever out of a rear wheel bearing was 5000 km, because I bought aftermarket parts that turned out to be inferior. Back to the VW dealer for an original-equipment replacement. Cost probably double, but that one was still on the car when I sold it perhaps 150,000 km later ...

 

[RRiver]

For me and I think it goes for those in Jordan. I'd rather have a lawn ornament waiting for repairs, for whatever reason, than drive with a "more than less than inferior part." The high chance that the resulting costs will far out weight waiting on a certified part is way too much.

Tarek, once again, your idea is NOT repairing anything and you're playing with your reputation. What's the cost of that???????

 

[Tmoose]

"then we don't need for highly automated grinding machine for the full automation process. pencil grinder, on another hand, a small heat treatment oven will be adequate to accommodate 15 to 20 joints per batch."

Hi tarekzad,

I feel you are still glossing over several of the technical aspects of a high functioning repair.

What weld filler and weld process(es) are being used to repair the wear or spalling damage ?

As others said, The "pencil grinder" has no chance of achieving the dimensions and tolerances and surface finish required for the repair to have acceptable durability. I'm guessing the requirements are measured in a few microns/0.0001s ".

Unless the acceptable durability is measured in weeks, and I'd guess not very many of them.

=====.

Weld metal is merde compared to high quality forged steel in some very important aspects, freedom from porosity and inclusions, general internal cleanliness.

The VERY hard 2 mm deep case hardening is more or less reserved for the ball/roller paths.
Carburizing is a multi-step process. Induction hardening uses fancy powerful electrical devices.
I'm guessing Not really within the capabilities of a heat treatment oven.

 

[tarekzad]

Dear RRiver


as I said, it is not an existing business model and it is just an idea, raising the idea here is a place to brainstorm it, not to judge it since it doesn't exist yet.

I'm not confident of it is viability and all your valuable feedback and others are well appreciated and will be considered.

Without an acceptable level of countenance, I will not proceed with this business. as you said, reputation has a value and will not sacrifice it easily either hardly.