C beam sealer?
Thread Starter
Instructor
Joined: Jun 2004
Posts: 234
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From: 1987- L98, auto OH
C beam sealer?
I'm getting ready to remove (or at least loosen most of the bolts and slide to the side) my C beam so I can remove my driveshaft and replace my u-joints. The manual talks of putting a bead of sealer around the mating surfaces of the C beam and the differential and transmission. Why? What is this for? Do you need to also put it on the C beam and trans flat surfaces or just around where they mate?
What sealer have you guys been using for this? Is regular RTV ok, or is there something special I should be using? I can't imagine that you can get a bead all the way around where these two things mate as it looks like there wouldn't be room to put any on the inside mating edge because the C beam would be in the way. Any advice appreciated! TIA!
Brad
What sealer have you guys been using for this? Is regular RTV ok, or is there something special I should be using? I can't imagine that you can get a bead all the way around where these two things mate as it looks like there wouldn't be room to put any on the inside mating edge because the C beam would be in the way. Any advice appreciated! TIA!
Brad
Pro
Joined: Oct 2003
Posts: 550
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From: Hesperia California
I have an 89, and I have removed the drive shaft twice without moving the beam. I don't know if there is any difference in the yr. models. The Haynes manual says you have to move the beam, however I took the shaft out before I read the manual. No problem.
Try it before you go to all that work.
Try it before you go to all that work.
Safety Car
Joined: Apr 2004
Posts: 4,532
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From: Lahaina Hi
At times the C-Beam will pop and crack if you don't seal the metals.
I just use liquid nails.
I just remove my exaust and losen the drive shaft bolts, pry the shaft foward and wiggle it out .I would jack up the rear end.
I just use liquid nails.
I just remove my exaust and losen the drive shaft bolts, pry the shaft foward and wiggle it out .I would jack up the rear end.
Instructor
Joined: Nov 2001
Posts: 141
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From: Renton WA
C-beam sealer
I know why you're supposed to seal the C-beam. I had the tranny out in 02. I recently had it out again because the darn synchro assemblies were hosed. I now have locking sliders with new assemblies in there. When I get the car back together, I'll see how that works.
When I removed the C-beam out last, water came out when I pulled the bolts out. The sealer is to prevent water from pooling in the pockets between the bolts and the transmission tailhousing and rear axle housing. In areas with salt this can promote serious corrosion. My car was parked in the garage for at least 6 months before I removed the C-beam and it still had water in there.
Not really sure what to seal it with. The original stuff seemed to be rather brittle and easily removed. I didn't seal it last time because I couldn't figure out how to get sealer all around the bolts without making a mess. Besides the sealer I have is so tough I might not have been about to get it apart. I use Dirko grey elastic filler. The stuff dries slow, but good luck getting it apart. You could install an oil pan with no bolts and it would stay on!!
When I removed the C-beam out last, water came out when I pulled the bolts out. The sealer is to prevent water from pooling in the pockets between the bolts and the transmission tailhousing and rear axle housing. In areas with salt this can promote serious corrosion. My car was parked in the garage for at least 6 months before I removed the C-beam and it still had water in there.
Not really sure what to seal it with. The original stuff seemed to be rather brittle and easily removed. I didn't seal it last time because I couldn't figure out how to get sealer all around the bolts without making a mess. Besides the sealer I have is so tough I might not have been about to get it apart. I use Dirko grey elastic filler. The stuff dries slow, but good luck getting it apart. You could install an oil pan with no bolts and it would stay on!!
Large Impressive Member
Joined: Jul 2003
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by Duntov85
I know why you're supposed to seal the C-beam.
When I removed the C-beam out last, water came out when I pulled the bolts out. The sealer is to prevent water from pooling in the pockets between the bolts and the transmission tailhousing and rear axle housing.
When I removed the C-beam out last, water came out when I pulled the bolts out. The sealer is to prevent water from pooling in the pockets between the bolts and the transmission tailhousing and rear axle housing.
Race Director
Joined: Jan 2005
Posts: 10,641
Likes: 13
From: Slidell Louisiana
Originally Posted by Movnviolation
I have an 89, and I have removed the drive shaft twice without moving the beam. I don't know if there is any difference in the yr. models. The Haynes manual says you have to move the beam, however I took the shaft out before I read the manual. No problem.
Try it before you go to all that work.
Try it before you go to all that work.
I can remove the driveshaft out of my 95 A4 without messing with the C beam.
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Thread Starter
Instructor
Joined: Jun 2004
Posts: 234
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From: 1987- L98, auto OH
Wow! Thanks for all the good replies. Now I know why they are asking for this. It makes sense now. I'll try the RTV stuff and see how it goes.
On my '87, it is impossible to get the driveshaft out without at least loosening the C beam and sliding it over about an inch. You don't have to pull it all the way out, but without moving it over, there is simply no way to get the shaft out between the C beam and the floor pan. Really tight in there. As it was, with the C beam moved over an inch or so, you can pull the shaft out to the rear and just clear the emergency brake cable. I left the cat converter in there, no need to remove the entire exhaust system on this one.
Again, thanks!
Brad
PS- Does anyone know why the front driveshaft yoke to the transmission has a large flange on it? It almost looks like a mini-harmonic balancer with a rubber ring between an inner and outer hub kind of thing? Never seen a yoke like this before.
On my '87, it is impossible to get the driveshaft out without at least loosening the C beam and sliding it over about an inch. You don't have to pull it all the way out, but without moving it over, there is simply no way to get the shaft out between the C beam and the floor pan. Really tight in there. As it was, with the C beam moved over an inch or so, you can pull the shaft out to the rear and just clear the emergency brake cable. I left the cat converter in there, no need to remove the entire exhaust system on this one.
Again, thanks!
Brad
PS- Does anyone know why the front driveshaft yoke to the transmission has a large flange on it? It almost looks like a mini-harmonic balancer with a rubber ring between an inner and outer hub kind of thing? Never seen a yoke like this before.
Burning Brakes
Joined: Nov 2001
Posts: 812
Likes: 1
From: Sherman Texas
That is a damper, or balancer on the front yoke. Many large trucks and buses use one to keep driveshaft harmonics from being annoying. When i had mine out, I removed the outer hub and had the driveshaft balanced, because the elastomer on mine had cracked and looked bad. Runs fine without it, no driveshaft vibration.
Chris
Chris
Thread Starter
Instructor
Joined: Jun 2004
Posts: 234
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From: 1987- L98, auto OH
Thanks for the info on the driveshaft! Wow, it looks like I guessed right on that thing! Mine looks ok, so I'll likely leave it alone. I'm taking the shaft in to the machine shop to get the joints replaced. Hopefully by Thursday I can get this thing back on the road. I only hope it solves the noise problems I've had from this thing! Again, thanks!
