Nissan Repair: 94 nissan altima uneven braking, nissan altima, brake dust

Question
QUESTION: Dear Calvin, I have had a 94 nissan altima for six and a half years starting with 126000 miles and now I have 262000 miles and ever since I've had it, when I have to slam on the brakes the right front wheel locks up very easily.I do not have abs.When the car gets dirty the left front wheel has minimal brake dust while the right front wheel will have a ton more brake dust.I have replaced both front calipers and brake lines and changed the fluid and it hasen't changed the uneven braking. I have gotten somewhat used to it but in the rain or snow it is very dangerous because of how easily it locks up, which kills my stopping distance and braking control. I have the stock proportioning valve but from what I understand it only proportions front to back not left to right.Any thoughts. thank you for your time and wisdom

ANSWER: HI Kevin -

You are correct. The proportioning valve balances the brake fluid from front to back being that there is a lot more travel to the back. Without that valve upon emergency braking, the car will fishtail.

However, there is still a chance that it could be the proportioning valve if there is debris stuck in it.

But, first of all, I would check the caliper. Was it a rebuilt caliper? Seems to me that it is a defective right caliper. Can you take it back to exchange? If not, try to overhaul it and see if that works, or better yet, just get another one. I really cannot think of any other reason why the brakes should lock up like that.

Hope this helps -
aloha
calvin

---------- FOLLOW-UP ----------

QUESTION: hey Calvin, today I to swapped calipers L to R just to try to see if it made any difference in the lockup and it was still locking up on the right side. do you think it could be my master cylinder.

Answer
Hi Kevin

Gee, how did you switch it? The brake hose and bleeder valve would be reversed and you would not be able to bleed the air out of the caliper by switching sides because the connection will be on the lower part of the caliper.

Anyway - The master cylinder divides only back and front, not left and right.

With the brakes locked up, try opening the bleeder valve on the caliper. If brake fluid does not shoot out and it does not release the wheel, then the caliper is defective. If it does release the wheel, then you are getting uneven pressure somewhere, and I would check the proportioning valve, perhaps bleeding each connection going to and from it.

aloha
calvin