Anyone running Compbrake top mounts?

[Rusty]

If you have some and can take a couple of measurements, then please let me know. I need the ID and OD of the top surface and the height of the threaded section, as well as the thickness of the lock ring. To the nearest mm would be fine; I've had an idea

[jade]

If you have some and can take a couple of measurements, then please let me know. I need the ID and OD of the top surface and the height of the threaded section, as well as the thickness of the lock ring. To the nearest mm would be fine; I've had an idea

I have a set waiting at the post office will check when i pick them up if you still need the info

[Jonnybravo]

Eeek Compbrake !

I hope the ones I suspect your making Rusty are better than most of the sh*te they sell.

[my2000apb]

Eeek Compbrake !

I hope the ones I suspect your making Rusty are better than most of the sh*te they sell.

why are they ****** mounts?

[Jonnybravo]

Compbrake stuff is mainly rubbish, always has been. Same when it was TAS

[Rusty]

mine are about 5-6 times the cost

I was thinking about another solution.

When you say crap, do you mean the bearings? The rest is anodised alloy, so is much of a muchness.

[Jonnybravo]

For the top mounts yes the bearings are crap but in general their products are naff !

[Rusty]

OK, fair enough. Was thinking of a cost effective solution to the topmount question but it would appear that my thoughts aren't going to come to anything, due to problems with the base product.

[K Simmonds]

They may not be an item I'd buy but to be fair to the Compbrake mounts the set fitted to my car when I got it are still in very good order. I've done over 10K miles on them and the previous owner had done a few as well. Andy- I can get the dimentions you need over the weekend if no one else has helped by then..

[Rusty]

OK, cheers, would be good to know. If they're not any good as a basic product, there's little point in modifying them to be more user friendly.

[re2500]

Ive got a set in a box in my dads garage, ill get the dimensions for you over the weekend.

[Jonnybravo]

The bearings they use are rubbish, thats certainly the fault with their top mounts.

The Vauxhall rose jointed tie bar brackets I have used in the past knocked from day one and 3 sets later still did the same, Peugeot bottom arms didn't fit amongst other problems.

I think generally its a issue with poor bearings on most of their stuff but why sell something designed for "motorsport" that can't usually deal with a 1000 road miles, if that, or if it actually even fits in the first place !

Top mounts beside the bearings are ok but they still screwed up newer designs meaning you have to cut the strut where as with other brands and strangely even the old TAS ones you didn't. TAS I believe folded and ended up as Compbrake, I'm sure I have heard someone say otherwise but strange how the catalogue is full of the same old tat lol

Rant over

[s2martyn]

my top mouts have lasted less than 1500 miles

[VAP]

While I wouldn't know Compbrake from a bowl of pineapple soup soup I can certainly identify/empathize with their plight. But cannot understand why they continue the course. I tried making solid mounts years ago. Made several hundred in fact and they sold like crazy, fast as I could produce them! Even had a bearing company's engineers custom-design PTFE-line spherical bearings for me and "guaranteed" they would give essentially lifetime service. Boy, do they and I regret that move!

One has to understand that any spherical bearing's true strength is in its use in a "radial" application. They are incredibly strong and long-lived when used in that orientation. You probably know those from other terms such as Heim joints, rod-ends, rose joints etc among others. Now turn those same bearings on to their sides and attempt to use them as we would in a strut mount application and it becomes an "axial" load situation rather than radial in use. Exceedingly high radial numbers fly out the window and strength plummets. In steel-to-steel sphericals high heat occurs and scoring/gauling of the ball/race occurs without constnt lubrication. Choose a PTFE-lined bearing and the PFTE-liners get flattened allowing "slop" between the spherical ball and the concave race. This occurs VERY quickly due to the spherical bearing being mounted in a "hard" non yielding/compliant housing. Not altogether different than sitting a spherical bearing on concrete and thwacking its race with a hammer.

Of course the lowered axial strengths related to the actual spherical ball and race can easily survive the spherical's axial orientation but the PTFE liner simply cannot and will not! A non-lined bearing can but now you have to R&R them frequently from their housings for lubrication. Given the work involved that is not a viable alternative to me or my customers. Maybe on an all-out race car but not for anything remotely close to a daily driver or even a dual use vehicle!

PTFE while an excellent sealing/lubricating material has no memory or resiliance whatsoever! If you sit a 1" sqaure block of urethane or rubber on a hard surface and smack it with a hammer repeatedly, it always springs back, never showing the hammer blows. If you try that with an identical block of PTFE it "dents" everywhere its struck by the hammer, and that dent remains forever!

Conversely if you put a spherical bearing in a compliant/resiliant housing instead of a solid/hard housing you could now begin to strike the bearing with a hammer and the PTFE liner inside doesn't "dent" or take a set like it did formerly. Because now much of that hammer blow has been absorbed by the cushioning of the rubber/urethane insulating material between the bearing and the harder surface beneath it.

In practical testing I could take a much cheaper PTFE lined spherical bearing than those I used in my solid mounts and make it live far longer than the super-spendy bearings used in my solid mounts. In fact "cost" and/or spherical bearing size didn't transfer to any positive benefit in the short run. It did however later, when longevity became impportant.

Take two identical spherical bearings, install one in a solid alloy mount and install it on either left/right front corners of a small-chassis Audi. Install the other spherical bearing in an OEM strut mount and install it on the opposite corner. The solid mount spherical bearing will be toast in a few weeks. The spherical bearing in the OEM mount will still be in near-perfect, pristine condition 6 years later! Yes, I did say "the EXACT same bearing will be in near-perfect, pristine condition 6 years later!!!"

Now how do ya suppose I would know such a thing? Well, why do you think there are Pro-Mounts today with PTFE-lined spherical bearings but no solid mounts available from me any more? Oh and whatever became of all those custom-designed, high-load spherical bearings used for solid mounts? They're still around but used in Pro-Mounts today instead of solid mounts. And all those solid mounts... well that's the worst part about this; I had to eat em! Every damn one of em!

Bottom line, least for me is I do not personally believe ANYONE is EVER onna get ANY PTFE-lined spherical bearing mounted axially to live in a solid mount for any significant time before issues arise. I don't care who they talk to or have engineer the bearing I just don't believe it will live! I've had the best in the business try it and say it could be done and now have backed away from those claims. And yes, they warranteed EVERY spherical bearing they made for me that was installed in a solid mount. In fact they still do on any spherical that fails in-use in a Pro-Mount of which, as I've said previously, there has been 2-3 maybe 4 over the years.

[mcandmar]

Interesting read there, thanks for that. I've used the Compbrake mounts which were done after 2 years, the bearings had worn out to the stage they were rattling. The ProMounts i replaced them with will probobly need replaced very soon too. I've had probobly four years out of them but i found recently when i had them out one was almost seized up, basically water must have got in and started corroding them. Managed to free them up with lots of WD40 but i dont expect them to last long. Would be nice to have the bearing sealed someway if at all possible, would improve the life conciderably with our weather.