I have a 68 coupe with power, 4 wheel disc brakes. They worked fine a few years ago but after sitting a few years the right front is slow in activating which causes the car to pull to the left real hard. I run silicone brake fluid which has been in there for the last 20 years so no corrosion was found in the caliper. I rebuilt the right front caliper even though it did not need it and bled the system with no improvement. I replaced all the rubber lines w/ss braided teflon hose with no affect. Could the distribution block be causing this? I know it has o-rings in it that might have come apart and plugged the line but the brake light switch does come on when bleeding the system. Has anyone had this problem? Tim
If your front brakes are good and getting good pressure you could try checking out the rears. Depending on the shape of your brake lines there could be rust and gunk built up in there from over the years, of course if you've had the same fluid in there for 20 years that can cause it's own problems.
interesting problem .... extreme pulling to the left as you describe is likely due to no or little line pressure at the right-side caliper ..... but since you said that you rebuilt that caliper and bled the system means that you should have had lots of brake fluid flow to that caliper -- corect ?? .... if so, then there shouldn't be a blockage in that right side line anywhere .... wrt to "o-rings" -- I'm not familiar with "o-rings" used in the distribution block as I thought that those were double-flare fittings and "o-rings" are not used/needed ..... in fact I'm not aware of "o-rings" being used anywhere in the brake system, at least for the OEM setups -- they all use double flare fittings except for the flex hose-to-caliper, which has a copper washer .... if you crack the right side bleeder and push on the brake pedal, you should get a good stream of fluid with a "soft" pedal .... then while still pushing you close the bleeder, the pedal should immediately firm up ..... but this is all very puzzling .... additional info may help if you're so inclinded to provide some .... good luck .... --67GTFB
There is a good video on west cost clasic cougar, on how to rebuild the distribution block. It sounds more like a gunky caliper/piston sticking in the bore to me.
#1-I have personally heard/read few good things about silicone brake fluid, especially in long term applications. Also gumming/clogging/clumping if any moisture or DOT 3 contamination. #2-Beyond checking all brake system parts and before rebuilding/replacing all of them, might I suggest that you check all suspension components, bushings, etc? What I'm getting at is that the problem may not actually be the brakes. For example: if the strut rod on the left is loose or has crumbled/worn bushings, it could easily cause your stated symptoms. Other worn/loose parts could do the same. Just A Thought Or Two, Gene
Yeah - that's what I was thinking too. If there are any loose or worn suspension components it can cause symptoms as described. Of course the brakes themselves are the best place to start.
Thanks for the responses! I have found no rust or corrosion in the brake system as is one of the plus's for silicone brake fluid. The o-rings I am talking about are on the brake light switch, spool which is located inside the distribution block. Years ago I had it apart and noticed the o-rings were a little worn with cuts and wanted to replace them but they did not sell a rebuild kit for the distribution block back then. Maybe a little piece of the o-ring fell into the brake line and slowed the flow? I have not had time to do any further troubleshooting but all the brake lines are SS so no rust has been found anywhere. My next plan is to disconnect both ends of the right front brake line and blow compressed air through the line to see if anything comes out. I did notice the flow to the right side was not as much as the left side when I was replacing the brake hoses. The suspension is all tight as this car is not driven very much to the point of only have less than 100 miles put on it in the last 5 years. The car tracks straight down the road until you step on the brake pedal. Tim
OK, thanks for the extra info .... I forgot about the internals of the distribution block, so my bad on that .... that may be the cause but if those are bad, I would expect fluid to leak out around the switch ??? .... well, we can conjecture all day long .... I agree (fwiw) with your next steps to tear the brake lines down and blow them out .... one of those PITA things to do .... suggest replacing the distribution block too .... good luck .... let us know how things turn out ....
Well I worked on it last weekend and I should have studied the distribution block more carefully. On a 1968 Mustang the master cylinder brake line comes into the top of the distribution block and the left brake line comes into the front and the right brake line comes out the bottom. It makes sense now that all the trash would accumulate into the bottom of the right brake port slowing the flow. I blew out that line and that fixed it. Unfortunately I used a dirty rag to catch all the fluid so I could not tell if a chunk of something was blocking it or it was just a buildup of sludge. Thanks for your input! Tim
