1969 GTO - Pulls to Left When Braking - Pontiac GTO Forum
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post #1 of 14 (permalink) Old 06-25-2019, 07:09 PM Thread Starter
 
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1969 GTO - Pulls to Left When Braking

Hi All,

Oh the joys of owning an old car! Lately I've had an issue where my 1969 GTO pulls noticeably to the left when I brake. It's noticeable enough that I have to counter steer to the right when braking. On one occasion I had someone cut me off in traffic and hit their brakes hard, requiring me to brake VERY hard which started to rotate my car due to how much heavier the left front braked versus the right front!

This past weekend I bled the brakes (which was badly needed) but on a low speed test drive it still felt like my old Goat was pulling to the left when braking. The front brake pads still have tons of material left, and the rotors are in good shape as well.

I'm planning to pull the front wheels again and maybe pull the front calipers to inspect them for any issues. Also, I noticed this past weekend that when I jacked up the front of my car (on level ground) the LF wheel had barely left the ground by the time the RF was several inches off the ground. I'm going to check that the front shock isn't cracked or broken, but I assume it's fine as there appears to be no suspension issues at all when I'm driving.

Could a suspension issue cause braking problems like this? Any other ideas what could cause this issue or what I can check?
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post #2 of 14 (permalink) Old 06-25-2019, 07:35 PM
 
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Originally Posted by GeeTO400 View Post
Hi All,

Oh the joys of owning an old car! Lately I've had an issue where my 1969 GTO pulls noticeably to the left when I brake. It's noticeable enough that I have to counter steer to the right when braking. On one occasion I had someone cut me off in traffic and hit their brakes hard, requiring me to brake VERY hard which started to rotate my car due to how much heavier the left front braked versus the right front!

This past weekend I bled the brakes (which was badly needed) but on a low speed test drive it still felt like my old Goat was pulling to the left when braking. The front brake pads still have tons of material left, and the rotors are in good shape as well.

I'm planning to pull the front wheels again and maybe pull the front calipers to inspect them for any issues. Also, I noticed this past weekend that when I jacked up the front of my car (on level ground) the LF wheel had barely left the ground by the time the RF was several inches off the ground. I'm going to check that the front shock isn't cracked or broken, but I assume it's fine as there appears to be no suspension issues at all when I'm driving.

Could a suspension issue cause braking problems like this? Any other ideas what could cause this issue or what I can check?

Check tire air pressure - something simple can do this.

Alignment?

Bad bushings - may be worn parts causing a change/**** the suspension angle on just one side rather than even braking.

Wheel bearing too loose or too tight?

Disc pads are cheap enough, throw another set on, but use the more inexpensive brand. The higher grade are typically metallic and this could be causing a problem - one side having more metal in the pad than the other might grab differently.

May even be a back brake causing the car to pull left. If one of them is too tight or not working, this may have an effect on braking and you think it is the front's. Just another free thing to check.
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post #3 of 14 (permalink) Old 06-25-2019, 08:45 PM Thread Starter
 
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PontiacJim - I did already check air pressure and I'm even at all four corners, plus the alignment seems okay because the car never pulls when driving only when braking.

Good idea about the wheel bearing I'll check for play, and I'm going to have a look over the front suspension this weekend (hopefully) and will check the bushings, etc as they're mostly old.

Also, good point about the rears maybe factoring in. I did have the rear drums off this past weekend when I bled the lines and the shoes and drums were in great shape and there are no leaks from the rear wheel cylinders. I did not adjust the "star" adjuster though to make sure the shoes are properly adjusted. If I'm not mistaken you can semi-hard brake while reversing and the force from braking adjusts the shoes outwards towards the drum, so I'll try that.
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post #4 of 14 (permalink) Old 06-26-2019, 05:41 AM
 
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Check the RF caliper, might be frozen or not sliding. I had the same problem on mine. A set of new calipers solved the problem. Sounds like you are getting no braking from the RF. JUst something else to check.
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post #5 of 14 (permalink) Old 06-26-2019, 05:47 AM
 
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Just had another thought. Flexible brake line, sometimes they can collapse in the middle not allowing flow.
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post #6 of 14 (permalink) Old 06-26-2019, 11:59 AM
 
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As far as a flexible brake line goes, it wouldn't collapse, but actually expand. A lower radiator hose can collapse without its internal spring to maintain shape from the sucking of fluid by the water pump. But the brake fluid is being pushed toward the caliper from the master cylinder not from it, the softer than steel brake line hose would expand in size causing a drop in pressure and less force exerted against the caliper piston. A stainless braided brake line does a better job containing the brake line from expanding although not stock in appearance. An old hose, expanding more than stock, would cause the wheel to have degraded braking force, so the right side is more likely in your case if that is the root cause.
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post #7 of 14 (permalink) Old 06-26-2019, 07:19 PM
 
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Brake lines collapse for several reasons. Typically, metal lines collapse from impact and rubber lines collapse due to age. ... The rule of thumb is usually if the vehicle pulls to one side while braking and the caliper shows no damage, then replacement of the brake hose is required.Jan 27, 2012
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post #8 of 14 (permalink) Old 06-26-2019, 10:02 PM
 
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Yes I agree about checking the right front caliper and hose, caliper stick often because the slides are not properly greased. New pads without greasing the caliper slides happens. A clogged or ruptured internal caliper hose.

You can take the wheel off and have a helper press the pedal then spin the right rotor by hand...will it spin? If it spins the caliper piston is not exerting pressure on the rotor or the shoes on the drum if you have drum brakes. Look over the hose as well, sometimes their is visible damage, other times internal failure, but if blocked the caliper or cylinder will not deploy the brake pads or shoes.

Also check your fittings at the master cylinder for leakage at the line that goes to thr right front wheel, a small leak can cause the caliper or cylinder not to properly deploy.

Stay with it you will get it!,
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post #9 of 14 (permalink) Old 06-26-2019, 10:07 PM
 
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Also check for broken spring on right front or A arm jammed in to sway bar, the upper ball joint and generallylook over the suspension for not letting the right side drop.....that should be a visible difference.....
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post #10 of 14 (permalink) Old 06-27-2019, 07:08 AM
 
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If the car is not pulling when you are driving, then your alignment, tire pressure, and suspension are fine.....Pulling when braking is an indication of a brake issue. Since your car is pulling to the left (hard) when braking, that is an indication that the left side of the car's brakes are working better than the right. As others have suggested, with the car on jack stands, spin the tires as a friend applies the brakes. Most likely the piston in your caliper (or drum) is stuck (fully or partially). If so, a simple rebuild should suffice. Good luck

1965 GTO Convertible 3 speed tri-power drum brakes originally

Current setup:
400 cu in with tri-power
4 speed Muncie
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