brake line pressure testing?
Thread Starter
Safety Car
Joined: Jun 2005
Posts: 3,775
Likes: 4
brake line pressure testing?
ive got a 69 thats pulling to the left, hard, under braking. ive got new rubber brake lines on both fronts and new calipers. neither has made a real difference yet. also have put a new MC and freshly rebuilt booster on a few years ago. pads and rotors are a couple years old too, but still like new.
the lines have been bled, stopping power is excellent, and the brakes feel excellent, with the notable exception that the car pulls hard to the left still. its better with all the new gear, but its still an issue
ive checked the suspension components (all new within the last 6-7 years) and everything is fine there.
which leaves me with pressure checking the lines them self. im hoping to see if both sides are equal, or if the drivers side is much lower than the pass side.
the lines have been bled, stopping power is excellent, and the brakes feel excellent, with the notable exception that the car pulls hard to the left still. its better with all the new gear, but its still an issue
ive checked the suspension components (all new within the last 6-7 years) and everything is fine there.
which leaves me with pressure checking the lines them self. im hoping to see if both sides are equal, or if the drivers side is much lower than the pass side.
Last edited by another-user; Aug 16, 2017 at 02:52 AM.
Drifting
Joined: Jul 2004
Posts: 1,695
Likes: 65
From: Kissimmee fl
Finalist 2021 C3 of the Year - Modified
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St. Jude Donor '07
Not that this is your problem, but when my 69 started doing something similar a couple of years ago, pulling to the right when braking, it turned out to be the front tire was delaminating. A new set of T/As and all was good again.
Just something else to check.
Just something else to check.
Team Owner
Joined: Sep 2006
Posts: 31,200
Likes: 4,287
From: Westminster Maryland
Hi a-u,
The hard line from the distribution block to the left side rubber line connection is a very short one.
Have you, or would you consider, changing it?
Being so short it's pretty easy to develop a 'kink' in it.
Regards,
Alan
Is there ANY chance that's it's a problem with the RIGHT side NOT functioning?
The hard line from the distribution block to the left side rubber line connection is a very short one.
Have you, or would you consider, changing it?
Being so short it's pretty easy to develop a 'kink' in it.
Regards,
Alan
Is there ANY chance that's it's a problem with the RIGHT side NOT functioning?
Burning Brakes
Joined: Apr 2008
Posts: 1,222
Likes: 93
From: shelbyville West Michigan
definitely a pressure test would help isolate the issue. there is a tool for that, you need to find a shop that has one. you can't just stick a guage on a Tee in the line, as there are many variables beyond which affect actual pad clamping force. (piston COF, bracket flex, caliper flex, etc.)
Waekon and OTC both make one, look for a shop which has a brake pressure equalization test kit.
or if you are near me you can use mine.
Waekon and OTC both make one, look for a shop which has a brake pressure equalization test kit.
or if you are near me you can use mine.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
Is there ANY chance that's it's a problem with the RIGHT side NOT functioning?
Thread Starter
Safety Car
Joined: Jun 2005
Posts: 3,775
Likes: 4
Tires - ive already rotated them, no change, so the tires are fine.
metal brake line kink - this is something ive considered. kind of a last resort thing i think, as the lines are all original and i see no reason they should have kinked after 40 years problem free.
right caliper not working - doubtful, i have wear marks on those pads and rotors.
left caliper - unless ive picked up multiple bad ones, theyre working fine. the original set worked fine but had the same pulling problem. new ones worked fine (except one of the new ones is leaking, so i RMAd it and will be putting a 3rd one on this evening)
so i think the best thing i can do at this point is pick up a pressure gauge and test out the line pressure.
metal brake line kink - this is something ive considered. kind of a last resort thing i think, as the lines are all original and i see no reason they should have kinked after 40 years problem free.
right caliper not working - doubtful, i have wear marks on those pads and rotors.
left caliper - unless ive picked up multiple bad ones, theyre working fine. the original set worked fine but had the same pulling problem. new ones worked fine (except one of the new ones is leaking, so i RMAd it and will be putting a 3rd one on this evening)
so i think the best thing i can do at this point is pick up a pressure gauge and test out the line pressure.
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Melting Slicks
Joined: Mar 2005
Posts: 2,093
Likes: 297
From: Midlothian VA
ive got a 69 thats pulling to the left, hard, under braking. ive got new rubber brake lines on both fronts and new calipers. neither has made a real difference yet. also have put a new MC and freshly rebuilt booster on a few years ago. pads and rotors are a couple years old too, but still like new.
the lines have been bled, stopping power is excellent, and the brakes feel excellent, with the notable exception that the car pulls hard to the left still. its better with all the new gear, but its still an issue
ive checked the suspension components (all new within the last 6-7 years) and everything is fine there.
which leaves me with pressure checking the lines them self. im hoping to see if both sides are equal, or if the drivers side is much lower than the pass side.
the lines have been bled, stopping power is excellent, and the brakes feel excellent, with the notable exception that the car pulls hard to the left still. its better with all the new gear, but its still an issue
ive checked the suspension components (all new within the last 6-7 years) and everything is fine there.
which leaves me with pressure checking the lines them self. im hoping to see if both sides are equal, or if the drivers side is much lower than the pass side.
Intermediate
Joined: Aug 2016
Posts: 36
Likes: 4
From: Frisco TX
might not help but...
Total shot in the dark here but I had a similar but different issue a while back on the heels of replacing 4 rotors, fluid, and pads. In my case the car pulled even with the brakes off. I turned out that I had a very slightly bent spindle likely from a fender bender by previous owner. With the old rotors there was enough play for it to 'wobble' and not bind up but with all new hardware, there was no room for play and the brake pads were effectively engaged a bit when everything was bolted up tight. But I couldn't see it with the naked eye. But you could sure feel the overwhelming heat pulling the wheel off after just driving a few hundred yards to test. We swapped out the spindle from an old car and the problem was solved immediately.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
Does it pull left only on the first application during a stop and if you let up and apply the brake again it brakes straight ahead, or does it continue to pull left on the second application?