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Hello, second post here after saying hello on the new member/ intro thread.
Anyways, yesterday while replacing my 2 rear Michelin's at the local tire store I did my usual on the lift inspection and photo opportunity and noticed the rear axle CV boots especially the ones above the exhaust look horrible. I can only guess it's heat damage from the pipes and it appears that some type of coating on the rubber is flaking off. I did not see any leaks and the material brushes off somewhat, but was wondering how long they will last before a split/ crack leads to failure of the boot. In the interim I'm thinking after cleaning off all the affected areas, I would use exhaust wrap and high temp clamps to mitigate any further damage.
While my CV boats are not nearly this bad, the dealership noted that this was the wax coating/anti rust coating coming off. Are your CV boots actually punctured?
While my CV boats are not nearly this bad, the dealership noted that this was the wax coating/anti rust coating coming off. Are your CV boots actually punctured?
Thank's for replying.
No, I could not detect any punctures or cracks at all. I'm very comfortable working in and around my BMW and although my 330 boots are not that close to the exhaust, they aren't even close to looking this bad even after 12+ years on original rear boots. So this was new to me. This week I'm going to wash the entire underside and get the boots back to a clean new look and then coat them with a protectant followed by the exhaust wrap method.
Thank's for replying.
No, I could not detect any punctures or cracks at all. I'm very comfortable working in and around my BMW and although my 330 boots are not that close to the exhaust, they aren't even close to looking this bad even after 12+ years on original rear boots. So this was new to me. This week I'm going to wash the entire underside and get the boots back to a clean new look and then coat them with a protectant followed by the exhaust wrap method.
If my dealership is to be believed (which I'm not sure if I do), and it really is just a wax coating that is coming off, I wonder if the reason you're not seeing it on your 330 is because it doesn't have that coating? I know on my last Audi, it was just a traditional rubber CV boot with no coating whatsoever, so I just want to make sure you're comparing apples to apples here.
If my dealership is to be believed (which I'm not sure if I do), and it really is just a wax coating that is coming off, I wonder if the reason you're not seeing it on your 330 is because it doesn't have that coating? I know on my last Audi, it was just a traditional rubber CV boot with no coating whatsoever, so I just want to make sure you're comparing apples to apples here.
Correct. The BMW is just a plain rubber boot. The C300 boots most probably have a coating (wax,etc) that has flaked off. I'll research further to see if it's a product that I could re apply.
Correct. The BMW is just a plain rubber boot. The C300 boots most probably have a coating (wax,etc) that has flaked off. I'll research further to see if it's a product that I could re apply.
Thanks. Yeah please! If you find anything please let us know. I'd like to do the same, but I have no idea what this wax coating is!
Mine have 240k and never had chipping like this, I have been spraying them with silicon spray when im servicing the car and now il be using 303 aerospace plastic and rubber protectant. They still look like new, very odd, maybe my early 2008 didnt get this "protective coating", which doesn't really makes sense putting rust protector on rubber boots, looks like the Florida heat cooked them.
Looking at cv shafts on ebay they all seem to have this chipping, seems normal, I guess mine chipped away before my ownership.
Mine have 240k and never had chipping like this, I have been spraying them with silicon spray when im servicing the car and now il be using 303 aerospace plastic and rubber protectant. They still look like new, very odd, maybe my early 2008 didnt get this "protective coating", which doesn't really makes sense putting rust protector on rubber boots, looks like the Florida heat cooked them.
Looking at cv shafts on ebay they all seem to have this chipping, seems normal, I guess mine chipped away before my ownership.
I would'nt be worried, maybe just clean it off and spray some protectant on each boot.
Thanks for that eBay link. Picture #2 definitely looks like mine. Aerospace 303 is exactly what I'm planning on using along with exhaust wrap that my son has for his dirt bike pipe. And just for fun, after it's all cleaned up I'll mount a temp monitor near the boot and take before and after temp readings and I'll report back. (Kinda like doing that stuff)
Thx
I think the boots look 90% better and feel very soft.
I didn't want to get into painting the entire rear exhaust for obvious reasons. I think having the CV boots coated with silicone should definitely prolong the lifespan.
Most of the flake material came off. The rest was still stuck on the boots.
Update. I washed the rear axle and boots with a soft brush and removed whatever flaky material wanted to come off. Then I drenched all the boots with silcone. Using rubber gloves I was able to work the silicone into the boots making them nice and soft. After that I elected to skip the exhaust wrap as that seemed like overkill on a modern car. Instead, I masked off the exhaust pipes directly below the boots and covered those sections with 5 layers of high temp silicone. This stuff should dramatically lower the heat soak factor immediately above the pipes especially white sitting in traffic. I couldn't find the thermal heat gun so no temp readings. As a preventive measure I'll be coating the boots again during every oil change.
Last edited by C300DD; 03-13-2018 at 05:44 PM.
Reason: Typo
At the factory when they put everything together, they paint everything black.. This is just black paint peeling/cracking off the boots and this is perfectly normal. The only time I would worry is if you had a tear and it was slinging grease around the underside of the vehicle. Nothing to worry about with the paint just flaking off.
03-11-2018, 11:53 AM
