Pulling brakes

gazzol

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Hi guys I'm looking for a little help. As per the title my brakes pull to the right and the harder you brake the harder they pull. In an attempt to cure this I have changed the brake pads and checked the pistons were all free to move out and push back easily and bled the brakes all to no avail they still pull. I have put the car in the rolling road brake tester and the brakes pull evenly when tested individually ie both figures are within a few Kg of each other and when tested at the same time they pull up very evenly. This isn't a recent issue for as long as I can remember the car has been like this, so I'm wondering if it is possibly a suspension or alignment issue? Is this something that anyone has come across before? Thanks in advance.
 
Could be toe adjustment but the car would probably wander on the road somewhat also. I'd start by swapping the front wheels.
 
My 2 cents here... in 20 years I’ve never seen a toe alignment cause a pull.
Caster and camber yes but not toe.

“toe in (or out, or both) can definitely make your steering wheel crooked when driving straight, but it almost never causes a pull.”


Check your tire pressure, check the temp of your rotors and swap your tires.
If a tire swap stops the pull remember there is no camber or caster adjustment on an e9.
 
I've driven cars that don't know which direction they want to go when the toe is out too far but I don't know if braking would cause it. Swapping the front wheels/tires from left to right would tell you if it's tires and not brakes if it follows the tire. I've also had worn steering do strange things ..
 
Hi guys I'm looking for a little help. As per the title my brakes pull to the right and the harder you brake the harder they pull. In an attempt to cure this I have changed the brake pads and checked the pistons were all free to move out and push back easily and bled the brakes all to no avail they still pull. I have put the car in the rolling road brake tester and the brakes pull evenly when tested individually ie both figures are within a few Kg of each other and when tested at the same time they pull up very evenly. This isn't a recent issue for as long as I can remember the car has been like this, so I'm wondering if it is possibly a suspension or alignment issue? Is this something that anyone has come across before? Thanks in advance.

Easily overlooked is the road surface and, in particular, what is often termed "road crown pull." This, of course, should be obvious with or without any braking application, but a minor drift can be magnified by braking. While improbable, if you have glazed brake pads or rotors, or even mismatched pads (not impossible), this can explain uneven braking on the road versus a test machine.

Swapping wheels is probably a good first bet toward diagnosis. However, you did not mention anything about the general condition of the front suspension or the steering linkage. Among other things mentioned by sfdon, are the wheel bearings properly adjusted? (Too loose or too tight could possibly affect steering, rolling resistance and braking.) Significant slop in the steering linkage, control arm bushes, strut (braking/radius) rods and related bushes or the lower joint can possibly permit the two front tires to take less than parallel tracks and this situation could be amplified by brake application. If one or both upper strut mounts is soft, distorted or cracked, this could, in practical terms affect the vehicle's camber settings too. (If memory serves correctly, there are two different length control rods and control arms. If the longer parts intended for the stretch sedans E3 are fitted on the E9, this can add camber. And, mixing and matching is a no-no, if symmetry is to be achieved.)

Hate to mention it, but alignment settings can all be affected by accident damage, kissing curbs and pot holes, and by improvidently jacking or supporting the vehicle. (Generally speaking, placing a jack under a sway bar or strut rod is ill advised, not just because of obvious safety concerns, but the fact that the mentioned components can be bent.) Lastly, ahem, many frame/alignment shops have the capability of actually bending struts so that they might conform to factory settings, presumably to correct accident damage. Some shops deliberately deviate from factory recommendations, in racing applications - with modified suspensions, wheels and tires. While this may be well intended, it is atypical. (I'm not saying that any of the above fits your facts, but maybe the possibilities are worth considering.)





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I have put the car in the rolling road brake tester and the brakes pull evenly when tested individually ie both figures are within a few Kg of each other and when tested at the same time they pull up very evenly.
After reading this again it seems that you have eliminated the brakes as the problem, or the "friction" aspect of it. It points to a directional problem. Something has to be changing under load to make the car move in that direction... back to loose steering joints, ball joints, tires...
 
Surprised no one has mentioned that the flex hoses can deteriorate internally and act as check valves for brake fluid which is supposed to freely pass through in both directions. You'll go mad trying to fix calipers, pads and alignment when the real cause of your pull-to-one-side might simply be the flex hoses. It's not a rare thing, I've had to deal with it on two coupes.
 
Surprised no one has mentioned that the flex hoses can deteriorate internally and act as check valves for brake fluid which is supposed to freely pass through in both directions. You'll go mad trying to fix calipers, pads and alignment when the real cause of your pull-to-one-side might simply be the flex hoses. It's not a rare thing, I've had to deal with it on two coupes.

Was going to mention this. I think it was actually @sfdon that me mentioned this to me.
 
Thanks for the the replies guys. I will try swapping the front tyres but they are a matched pair and directional so I'd have to swap them straight back, the only time I've come across tyres being an issue was when two grossly miss matched tread patterns were fitted ie 1 winter/snow tyre and 1 summer on the same axle but in those cases it's caused the car to pull all the time and not just when braking. I'm going to take the car into the workshop and properly strip down the caliper on the left hand front and take the pistons out and make 100% sure that nothing is sticking even slightly. I know that it isn't the rears because I have a bias adjuster and wound off the rear brakes and the pull was still there. As for road crown...no, if I drive (momentarily) on the wrong side of the road it's still there. If it isn't the caliper then I will have to look into the front caster and camber. The front camber was very slightly off the last time I measured it but I've never measured the caster and don't even have the equipment to do so.
 
Surprised no one has mentioned that the flex hoses can deteriorate internally and act as check valves for brake fluid which is supposed to freely pass through in both directions. You'll go mad trying to fix calipers, pads and alignment when the real cause of your pull-to-one-side might simply be the flex hoses. It's not a rare thing, I've had to deal with it on two coupes.
Good point but I should have mentioned my hoses are stainless/teflon and when the rubber hoses do collapse they also cause the brake to stick on and overheat which is not part of my problem
 
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