TheSamba.com :: View topic - Sealing compound/replacing swing axle boots

Fri Jul 23, 2010 7:11 pm

Got the split boots, no instructions. Read through a few forums/tech articles, but don't know what "sealing compound" to use. A couple of my manuals say to "place a light coating of sealing compound on the joining faces of the boot". What do I use??

Fri Jul 23, 2010 7:59 pm

Personally have used a light coating of RTV.

Fri Jul 23, 2010 8:50 pm

COCO2009 wrote: Got the split boots, no instructions. Read through a few forums/tech articles, but don't know what "sealing compound" to use. A couple of my manuals say to "place a light coating of sealing compound on the joining faces of the boot". What do I use??

You shouldn't have to use anything as per any other responses I have ever seen regarding the use of the split boots. Just install them at either 10 or 2 o'clock position for the split as you are looking at them and they should remain leak free.

Fri Jul 23, 2010 10:20 pm

Aren't they rubber???? Bolt the halves together, they make a seal. Why add more? I've never used any extra sealant.

Sat Jul 24, 2010 7:47 am

Due to being rubber it can bunch or gap in places. VW more than likely used sealant more to keep out dirt/dust than to keep the gear oil in there.
Less dust = less friction/wear in the transaxle over time due to cleaner oil.

Sat Jul 24, 2010 7:50 am

They only bunch if you over tighten them. Use flat washers on each side to spread out the load, and just seat the rubber so it seals and doesn't bunch......it ain't rocket science. Been doing it this way for yrs, never had an issue.

Sat Jul 24, 2010 8:13 am

Sure it is not rocket science!
Still unless you have been having your gear oil lab tested you will never really know how dirty it is getting.
Time to apply some RTV is about 30 seconds and it isnot a huge deal to do when installing the rubber boots. If it really does not help, it will still not be a big deal to apply some.
Once again VW was the ones to have sealant in the instructions. Where were the VW scientists working?? Oh yes, at VW.

Sun Jul 25, 2010 5:38 am

what does your Robert Bentley say about it? wwmrd?

Sun Jul 25, 2010 8:36 am

I think it's in the manuals because way back some split boots were flat faced where they mate. Boots now have a labrinth with grooves and channels that vastly increase the surface area of the seal between them.
I have used a rubber cement type sealer before, but assemble before it drys. It helps mainly as a lubricant to ease assembly, the rubber sticks together dry and this makes it slippery and eases the mating of the two halves.
Bottom line is you don't really need anything with a good quality boot.

Sun Jul 25, 2010 6:48 pm

x2 on Hotrodvw. Never had to use any kind of sealant.

Sun Jul 25, 2010 11:53 pm

Eric&Barb wrote:
Time to apply some RTV is about 30 seconds and it isnot a huge deal to do when installing the rubber boots.
I bet you smear RTV all over O-rings too.

Mon Jul 26, 2010 12:55 am

Either way will work. One way will just piss people off because its not THEIR way.

Mon Jul 26, 2010 3:16 am

hemifalcon wrote: Just install them at either 10 or 2 o'clock position for the split as you are looking at them and they should remain leak free.

10 for driver side, 2 for passenger..........split towards front to keep grease away from the split as you drive down the road.

Mon Jul 26, 2010 7:29 am

Bruce wrote:
I bet you smear RTV all over O-rings too.

No, never done that.

Have you found in virtually all official VW manuals that one should??

Mon Jul 26, 2010 10:38 am

Michael Fischer wrote: Either way will work. One way will just piss people off because its not THEIR way.
My boots have no split. 8)

Max

Mon Jul 26, 2010 8:13 pm

Eric&Barb wrote: Bruce wrote:
I bet you smear RTV all over O-rings too.

No, never done that.

Have you found in virtually all official VW manuals that one should??
No, but every gearbox I pull apart that was rebuilt by someone else had RTV gooped all over the O-rings for the sidecovers.
My point is, rubber doesn't need RTV to seal.

Mon Jul 26, 2010 8:14 pm

vwsteve wrote: hemifalcon wrote: Just install them at either 10 or 2 o'clock position for the split as you are looking at them and they should remain leak free.

10 for driver side, 2 for passenger..........split towards front to keep grease away from the split as you drive down the road.
Where is the grease coming from?

How do you know which way oil is being flung around inside the boot?

Mon Jul 26, 2010 9:30 pm

Bruce wrote:
No, but every gearbox I pull apart that was rebuilt by someone else had RTV gooped all over the O-rings for the sidecovers.
My point is, rubber doesn't need RTV to seal.

If a piece of rubber is clamped between two pieces of steel as designed, then no sealant, sure.
Problem is the boots seam is not clamped in a continuous steel enclosure. So betting that is why VW states the need for sealant there.
Have thought of using the glue for door seals to glue the seam shut, but have not tried that. If you have a better idea of a sealant would be interested. Till then will keep with what has worked for us.....

Several times have been surprised with how much dust can get into the brake system even with full bleeding every two years! If dust can get into that system up front......

Tue Jul 27, 2010 7:55 am

Momentive RTV 157. Dries fast, remains flexible, almost impossible to scrape off. It's used when installing the door seals on pressurized airplanes. Your boots won't leak.

Tue Jul 27, 2010 10:21 am

Eric&Barb wrote: Several times have been surprised with how much dust can get into the brake system even with full bleeding every two years! If dust can get into that system up front......
Clean your front floor so you don't bump dirt in there. ;)

To put in my own 2 cents, I've never used a sealant and never had a leak except from the smaller boot end, which is always solved by adjusting the tightness of that smaller clamp. It can leak from there if overtightened.