CV boot longevity
#16
Pro
Join Date: Apr 2010
Location: Magnolia TX, just north of Houston, Red 1984 S
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Not to pick on any of the current suppliers, but I think the 4 pairs I have recently purchased all stink. The rubber is suspect quality wise. Worse yet, the clamps, when fully closed, do not lock the rubber to the housing on my '84. Too loose, and they leak grease at speed from aroung the large end of the boot. I just bought another set last week, and they are the same. IMO clamps are slightly too big for my CV housings. When clamped tight, as tight as the clamp allows, I can rotate the boot on the housing, by hand.....I would be happy to pay more for some that actually fit well......regards the OP's question, I believe there is only one boot kit being sold for both early and late CV / axle assemblies...
#17
Rennlist Member
I have a 79 but it has mixed axle types and there are at least two styles of flanges and boots from a inside the larger end design.
Top photo is a boot with a significant ridge on the inside. It is designed for the flanges with the deep groove (top flange pic).
The 2nd boot pic has a smoother inside lip and is designed for the smoother flanges (bottom flange pic).
I like the grooved flanges and ribbed boots as they seem to engage much firmer.
The non-welded style (each end bolts to the wheel/ transaxle) is OEM for the older cars and the new style (bolted on at transaxle and a welded unit that has a shaft secured by a nut thru wheel) is the newer style. Additionally there are kits with metal caps the cover the exposed grease on the non-weled ends for later cars that according to a write up here will work on the non-welded ends and keeps the grease from getting everywhere on reassembly.
I did not use those myself but wished I had and will the next time around.
See Sharkskins write up for the non-welded and Dwaynes for the welded.
http://members.rennlist.com/sharkski...ftsRematch.htm
http://dwaynesgarage.norcal928.org/boot.htm
Last edited by jwillman; 02-19-2011 at 11:52 AM.
#18
Rennlist Member
Not to pick on any of the current suppliers, but I think the 4 pairs I have recently purchased all stink. The rubber is suspect quality wise. Worse yet, the clamps, when fully closed, do not lock the rubber to the housing on my '84. Too loose, and they leak grease at speed from aroung the large end of the boot. I just bought another set last week, and they are the same. IMO clamps are slightly too big for my CV housings. When clamped tight, as tight as the clamp allows, I can rotate the boot on the housing, by hand.....I would be happy to pay more for some that actually fit well......regards the OP's question, I believe there is only one boot kit being sold for both early and late CV / axle assemblies...
#19
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Join Date: Apr 2010
Location: Magnolia TX, just north of Houston, Red 1984 S
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I had the same issue when I did mine and worked with Roger at 928srus over a few weeks to identify the right boots and clamps. I sent Roger a couple of PDF's with pic's and measurements and we finally found the right combination of boots and clamps. I have tried and post the PDF's here but they are too large.
#20
Rennlist Member
I have purchased 2 sets from Roger and 2 other sets from 2 other suppliers, all for an '84, and they have all been the same size made by the same folks, for my car the clamps are slightly too large, I think the rubber size is generally OK, or at least close enough if the clamps do their job ......I need to pull the axles again and do some measurements and get back to Roger I guess and see if there is a better solution...or maybe better yet, order some clamps that fit from Mc-Master Carr and forget the ones that come with the kit?....
He ended up sending me a different clamp from what was in the kit (bottom pic).
There were also clamps for the inboard shaft side of the boot but they were too wide for the space on the boot and I ended up no using a clamp at all. Went with a tie wrap instead.
#21
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Join Date: Apr 2010
Location: Magnolia TX, just north of Houston, Red 1984 S
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Jim,
Yes, that is precisely the issue I have, the clamp bottoms out before it really clamps the boot ....I have not yet installed the hose clamp solution but that was on the plan for today. I just got the last kit in yesterday from a 3rd source, with assurance that it was correct...it isn't, same as the rest. It is not a big deal, just very irritating piece of work to have to do more than once because of what I think are improperly sized parts from GKN.
Yes, that is precisely the issue I have, the clamp bottoms out before it really clamps the boot ....I have not yet installed the hose clamp solution but that was on the plan for today. I just got the last kit in yesterday from a 3rd source, with assurance that it was correct...it isn't, same as the rest. It is not a big deal, just very irritating piece of work to have to do more than once because of what I think are improperly sized parts from GKN.
#22
Burning Brakes
I replaced the boots on my 1986.5's right axle. Used a universal set of CV boots from the local autopart supplier. They actually fit really good and come with pretty good clamps as well.
Cost me 9 euro's per boot, have to wait and see about longevity ;-)
Removing the inner CV was a bit of a PITA though, took 3-leg puller and quite a bit of brute force to get it to slide of the axle.
Cost me 9 euro's per boot, have to wait and see about longevity ;-)
Removing the inner CV was a bit of a PITA though, took 3-leg puller and quite a bit of brute force to get it to slide of the axle.
#24
Can they be identified if they are Porsche "OE" or "OEM" quality replacement boots?
From the work we are now doing with rubber and rubber moldings, rubber formulations and the quality of the molds and molding processes used define the end product's quality and longevity, even if they initially look the same.
Porsche OE (Original Equipment) parts have to be made according to Porsche blessed rubber formulations and molding processes, while OEM (Original Equipment Manufacturer) just means the part was made by the same Porsche supplier but usually not with the same rubber formulas and molding processes, due mainly to licensing agreements between both parties.
Now take it a step further away from OEM and you are taking a chance that the part is close but not near the same quality as even the OEM part, let alone the OE part.
Sometimes buying a part because it's cheapest is always the best solution.
From the work we are now doing with rubber and rubber moldings, rubber formulations and the quality of the molds and molding processes used define the end product's quality and longevity, even if they initially look the same.
Porsche OE (Original Equipment) parts have to be made according to Porsche blessed rubber formulations and molding processes, while OEM (Original Equipment Manufacturer) just means the part was made by the same Porsche supplier but usually not with the same rubber formulas and molding processes, due mainly to licensing agreements between both parties.
Now take it a step further away from OEM and you are taking a chance that the part is close but not near the same quality as even the OEM part, let alone the OE part.
Sometimes buying a part because it's cheapest is always the best solution.
#26
Drifting
He may have typed that wrong, but I agree with Constantine's statement, cause it includes the word "sometimes".
I think Bill's got something there about the car sitting in one position, but my 90' S4 with factory cv boots and 95K miles had done just that for many years and the boots lasted for 20 years before developing cracks.
The outer boots seem to crack earlier due to heat exposure from the heat of the brakes and maybe some UV from sunlight.
Most CV boots are made from butyl rubber (synthetic rubber) which is excellent in terms of durability, but I have seen some them in silicone rubber too.
The outer boots seem to crack earlier due to heat exposure from the heat of the brakes and maybe some UV from sunlight.
Most CV boots are made from butyl rubber (synthetic rubber) which is excellent in terms of durability, but I have seen some them in silicone rubber too.
#27
Rest in Peace
Rennlist Member
Rennlist Member
Well I think I now have a set of 4 boots I can not use
They might end up as prizes @ SITP 2011, like I did with a new set of rotors once before
Jim,
Again thanks for taking the time to explain this for me an everyone else!
They might end up as prizes @ SITP 2011, like I did with a new set of rotors once before
Jim,
Again thanks for taking the time to explain this for me an everyone else!
Andre,
I have a 79 but it has mixed axle types and there are at least two styles of flanges and boots from a inside the larger end design.
Top photo is a boot with a significant ridge on the inside. It is designed for the flanges with the deep groove (top flange pic).
The 2nd boot pic has a smoother inside lip and is designed for the smoother flanges (bottom flange pic).
I like the grooved flanges and ribbed boots as they seem to engage much firmer.
The non-welded style (each end bolts to the wheel/ transaxle) is OEM for the older cars and the new style (bolted on at transaxle and a welded unit that has a shaft secured by a nut thru wheel) is the newer style. Additionally there are kits with metal caps the cover the exposed grease on the non-weled ends for later cars that according to a write up here will work on the non-welded ends and keeps the grease from getting everywhere on reassembly.
I did not use those myself but wished I had and will the next time around.
See Sharkskins write up for the non-welded and Dwaynes for the welded.
http://members.rennlist.com/sharkski...ftsRematch.htm
http://dwaynesgarage.norcal928.org/boot.htm
I have a 79 but it has mixed axle types and there are at least two styles of flanges and boots from a inside the larger end design.
Top photo is a boot with a significant ridge on the inside. It is designed for the flanges with the deep groove (top flange pic).
The 2nd boot pic has a smoother inside lip and is designed for the smoother flanges (bottom flange pic).
I like the grooved flanges and ribbed boots as they seem to engage much firmer.
The non-welded style (each end bolts to the wheel/ transaxle) is OEM for the older cars and the new style (bolted on at transaxle and a welded unit that has a shaft secured by a nut thru wheel) is the newer style. Additionally there are kits with metal caps the cover the exposed grease on the non-weled ends for later cars that according to a write up here will work on the non-welded ends and keeps the grease from getting everywhere on reassembly.
I did not use those myself but wished I had and will the next time around.
See Sharkskins write up for the non-welded and Dwaynes for the welded.
http://members.rennlist.com/sharkski...ftsRematch.htm
http://dwaynesgarage.norcal928.org/boot.htm
Last edited by Andre Hedrick; 02-21-2011 at 03:06 PM.