My '70 has standard brakes.

When stopping normally there is no pull. When I get on them aggressively, they pull significantly to the left.

Question: Do you think it a caliper problem or a proportioning valve problem or some other demon.

Swapping pads left/right and right/left keeps the problem to the left, so it's not a pad problem.

Any thoughts?

Thanks,

Frank

Could be unevenly adjusted rear brakes, or a partially restricted right front brake hose. How old are the hoses?

If the right side caliper is not working well, it will pull to the left under hard braking. Are they new calipers or originals?

Arne: The lines are original, as is the proportion valve. The flex lines are braided steel and are about 6 months on the car. I'll give the rear brakes a test tomorrow.

Xray: The calipers are relatively new (less than 3000 miles old).

Thanks for the ideas.

Frank

the biggest problem i say would be unevenly worn pads, probably due to wheel alignment or even long tern wheel off-balance, itd be easy to fix provided you had a pair of verniers

More dumb thoughts:

--Tire pressure normal? Does the car drive straight on a level road?

--Any crimps in the original brake lines? If one is creased or crushed, too little brake hydraulic pressure will get to the caliper, causing pull to the unaffected side.

--Is this a new problem, a problem since the calipers were added, or a problem of longer duration?

--I was under the impression that there is only a front/rear proportion valve, and the switch under the master detected changes in front/rear pressure but merely split hydraulic pressure left/right. It's possible the switch outlet for the right front line is partially blocked--has it been flushed out?

--any trouble bleeding the system? Any fluid leaks? When you replaced the calipers the bleed screw is on the top, right?

--A brief google search for "Brakes pull to left" shows that you're not alone. Sadly, no one else has any good advice....

Good luck,

xray: The problem began about half-way through a DE session in January. I had installed slotted/drilled rotors in December and was running them for the first time.

The left rotor blued during the session, so I swapped back the original solid rotors. The left s/d rotor was 0.009" out of true, the right s/d rotor was 0.000 and OK.

Car drives straight on a level road, no problem there. I haven't visually checked the hard lines, but shall.

skids280: Pads are relatively new <1000 miles now (stock) and the Hawk "blue" pads had that half DE session in January. It doesn't matter what pads I use, the pull to left remains.

I'll try to check the hard lines, rear brake adjustment today and add more info to the mix.

Thanks to all.

Frank

You've got uneven pressure to the front calipers, or a sticky caliper. Both the pull to the left, and the blued left rotor indicate that the left is working much harder than the right. If the flexible lines are stainless braid-covered teflon (and both are the same manufacturer), I strongly suspect the right caliper has a stuck piston.

I suggest that the left caliper MIGHT be dragging ever so slightly...not enough to feel under normal conditions but aggravated under heavy braking. The over-heated (blued) rotor is an indication of drag...check and clean the caliper slides and ensure the piston moves freely. Easy way to compare is to raise both front wheels - which wheel spins easier by hand??

GWGarrard

I persued every suggestion. I replaced both right and left calipers, springs and pins. Still, the problem persists, although to a much lesser degree. I'll be on the track the 17th and 18th and will report back with the results.

Thanks to all.

The cops gave me a good looking over when I went by their radar trap speeding up, then slowing down, speeding up.....:eek:

Should've bought 'em donuts.

Frank

Frank

Push on the brake pedal hard several times and then release the pedal. Now crack the brake bleeder and see if any brake fluid squirts out under a litttle pressure. If it does it could be the brake master cylinder not releasing 100% (wear in the clyinder). Check both calipers. You will have a small amount of fluid slowly trickle out when you crack it. But it should not be under any pressure.

Good luck

You need to also consider the proportion valve.

Try flushing the fluid from the master and the lines. Just a thought if you haven't already flushed all of the fluid.