brake line pressure testing?

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Aug 16, 2017 | 01:16 AM

another-user

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Safety Car

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brake line pressure testing?

ive got a 69 thats pulling 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.

oops, meant to put this in tech, not general. go ahead and ignore this.

Last edited by another-user; Aug 16, 2017 at 02:50 AM.

Aug 17, 2017 | 11:14 AM

MelWff

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if the car is pulling hard to the left, the problem is with the passenger side. Check if the pistons are binding. You replaced the calipers but kept the old pads? You are sure you dont have a problem with the passenger side rotor, glazed?

Aug 18, 2017 | 10:56 AM

doorgunner

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From: New Or-leens Loo-z-anna

Also.........Could the steel brake line that goes to the passenger caliper be damaged/rusted internally somewhere which would restrict the fluid pressure?

Aug 18, 2017 | 12:37 PM

7T1vette

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From: Crossville TN

A hard line would need to be nearly closed off to restrict pressure. The hard lines should be checked, but significant damage would need to be seen to have any concern about pressure drop (ie, crushed).

I'm leaning toward glazed pads on the right side. Are the rotors and pads on the front of the same manufacturers and vintage? Rotor material and surface finishing methods can have performance differences. When working on brakes, components need to be the SAME on opposite sides of front or rear wheels.

Last edited by 7T1vette; Aug 18, 2017 at 12:38 PM.

Aug 18, 2017 | 05:53 PM

terry82

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From: columbia city in

Take pads from one side and trade with the other side ,drive and see what happens. there is a gauge that will test brake line pressure.https://www.otctools.com/products/br...ssure-test-kit there are cheaper ones.

Jul 9, 2020 | 07:11 PM

derekderek

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From: SW Florida.

bleed the right again. and again. and again...

Jul 9, 2020 | 07:31 PM

Gold Dragon

Burning Brakes

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From: The Buckle of the Bible Belt. Joplin Mo

Quote:

Originally Posted by doorgunner

Also.........Could the steel brake line that goes to the passenger caliper be damaged/rusted internally somewhere which would restrict the fluid pressure?

This...I was thinking something similar. Had a Malibu that sat for a while. When it was road worthy again it would pull hard to one side. Turned out the steel line from front to back corroded. Only the fronts would work, and the dominant side would win. Could still get fluid out when bleeding...just not enough to push the rear brakes. Once the steel line was replaced

. Take the car out to a safe spot and jamb the brakes hard. See which wheels lock and which ones don't.