Brake piston lube
Elite HDF Member
Joined: Nov 2010
Posts: 3,846
Likes: 173
From: Simi Valley, CA
Silicon based fluid (DOT 5) is also more compressible than glycol based fluids, that is the reason for the warning that you may experience a softer feel. It also does not lubricate as well as glycol based fluids and I believe that is the reason most ABS systems do not use it.
Grand HDF Member
Joined: Dec 2007
Posts: 4,999
Likes: 55
From: Bay Area
Damn so many wrong answers. Always use a silicone based lube like silglide after washing everything down with alcohol. The caliper lube you used is fine. You have to remember there are quite a few dealer mechanics learned the trade as a back yard mechanic. NOT ALL but they are out there.
Thread Starter
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Cruiser
Joined: Dec 2010
Posts: 222
Likes: 2
From: Ohio
My 2000 RK calls out for dot 5 in the system. But not to use it for lubeing the pistons.
I guess the fluid is behind the piston not on the sides or it would leak.
The piston lube supplied with the new seals is 3 times thicker then the brake fluid. It is yellow like the stuff I cleaned out of the bores, factory looking stuff.
The Permatex lube I used in the front is twice as thick as the yellow stuff.
I choose to use the lube I did on front pistons, on the rear pistons and did not use dot 5 like the service manual said.
I will find out when it gets warm
Straightleg
I guess the fluid is behind the piston not on the sides or it would leak.
The piston lube supplied with the new seals is 3 times thicker then the brake fluid. It is yellow like the stuff I cleaned out of the bores, factory looking stuff.
The Permatex lube I used in the front is twice as thick as the yellow stuff.
I choose to use the lube I did on front pistons, on the rear pistons and did not use dot 5 like the service manual said.
I will find out when it gets warm
Straightleg
Elite HDF Member
Joined: Apr 2007
Posts: 4,984
Likes: 8
Your first post sound like you said not to use DOT 5 Brake fluid in the system.
I think the stuff you are using it fine.
This is what my 06 manual states:
CAUTION
Do not use D.O.T. 4 brake fluid for lubrication. Use of
D.O.T.4 brake flu id will result in increased lever travel.
1. Lubricate the following parts prior to assembly using a
I think the stuff you are using it fine.
This is what my 06 manual states:
CAUTION
Do not use D.O.T. 4 brake fluid for lubrication. Use of
D.O.T.4 brake flu id will result in increased lever travel.
1. Lubricate the following parts prior to assembly using a
light coat of G.E.
VERSILUB~ IIG322 L SILICONE
GREASE (marked "Piston Lube") from the service parts
kit. All other surfaces must be dry for assembly.
a. Lubricate nose radius and outside diameter of piston.
Apply lube to inside of caliper piston bores.
b. Apply lube to inside diameter of seals and wipers.kit. All other surfaces must be dry for assembly.
a. Lubricate nose radius and outside diameter of piston.
Apply lube to inside of caliper piston bores.
Last edited by tlb; Feb 3, 2011 at 07:04 AM.
Thread Starter
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Cruiser
Joined: Dec 2010
Posts: 222
Likes: 2
From: Ohio
TLB
So what they are saying from my year to your year is yes this is what brake fluid you put in your brake system just dont lube the pistons with it.
Use this thicker ge product.
I just used something other than the ge product because the dealer did not have it.
The stuff i used, I used on many a brake job on a car and truck with no issues.
Straightleg
So what they are saying from my year to your year is yes this is what brake fluid you put in your brake system just dont lube the pistons with it.
Use this thicker ge product.
I just used something other than the ge product because the dealer did not have it.
The stuff i used, I used on many a brake job on a car and truck with no issues.
Straightleg
Grand HDF Member
Joined: Dec 2007
Posts: 4,999
Likes: 55
From: Bay Area
Heres what I remember from the old days of gasket and sealing science. If you were to use the same (brake) fluid to lube a sealing surface, when that seal is made to hold back the same fluid (in this case a potential life threatening failure) it is going to leak, as you have made a film of the same fluid between the seal and bore/piston. Since the fluids have an affinity for itself it would be free to travel under the sealing surface. THATS WHY THE BOOK SAYS USING DOT WHATEVER WILL CAUSE SPONGY BRAKES.
Elite HDF Member
Joined: Apr 2007
Posts: 4,984
Likes: 8
i do not see why it would be an issue, they are just stating not to use the brake fluid to lube the piston.
I found it odd that my owners manual and covers say DOT 5 only, nut my service manual says DOT 4.
Permatex has been in business a long time, and is safe to use. HD just does not contract with them.
I will say when you fill the system, I did mine from the bleeder, which fills it in reverse. Bleeding the front brake was super easy.
I found it odd that my owners manual and covers say DOT 5 only, nut my service manual says DOT 4.
Permatex has been in business a long time, and is safe to use. HD just does not contract with them.
I will say when you fill the system, I did mine from the bleeder, which fills it in reverse. Bleeding the front brake was super easy.
TLB
So what they are saying from my year to your year is yes this is what brake fluid you put in your brake system just dont lube the pistons with it.
Use this thicker ge product.
I just used something other than the ge product because the dealer did not have it.
The stuff i used, I used on many a brake job on a car and truck with no issues.
Straightleg
So what they are saying from my year to your year is yes this is what brake fluid you put in your brake system just dont lube the pistons with it.
Use this thicker ge product.
I just used something other than the ge product because the dealer did not have it.
The stuff i used, I used on many a brake job on a car and truck with no issues.
Straightleg
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Stellar HDF Member
Joined: Apr 2005
Posts: 3,108
Likes: 9
From: Lincolnton, NC
I sold brake parts and components to the NASCAR guys for 20+ years. Nobody rebuilds calipers more than these guys ( after every race ). They never use brake fluid during the rebuild. We sold them a product called Rubber Grease that we purchased from Tilton Engineering. You can Google it but it's probably the same stuff as the Permatex.
Last edited by Neckball; Feb 3, 2011 at 06:31 PM.
