frozen caliper (not 944)
06-20-2007, 03:22 PM
#1
Burning Brakes
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frozen caliper (not 944)
I'll start by saying I need some help with my daily driver - NOT the 944 (*well, maybe I need help with that in general, but not today!).
My front calipers froze up on my '97 Nissan Sentra and did so over time, not abruptly. This post is because I don't feel confident that the only problem is with the calipers.
Cutting to the chase: I want opinions about my brake booster vacuum test (see below), and to learn any other tests that can be done before replacing the calipers, pads and rotors (already ordered).
More Info:
I pulled everything apart and all physical components look OK. Brake lines are in amazingly good shape; no kinks or undue bends.
The caliper cylinders compressed without "too much" trouble, but required decent leverage once off the car - and the pins were a rusty mess (part of the problem)!
I checked the brake booster by pulling its vacuum line to see if the calipers let go. Unfortunately, my verdict is out on that test... I pulled the vacuum - which was holding a fair pressure - but found the wheel still didn't turn freely. The pickle is, I could turn it with some muscle, but it was still much harder to rotate than before these problems crept up.
Any help is appreciated!
Thanks
My front calipers froze up on my '97 Nissan Sentra and did so over time, not abruptly. This post is because I don't feel confident that the only problem is with the calipers.
Cutting to the chase: I want opinions about my brake booster vacuum test (see below), and to learn any other tests that can be done before replacing the calipers, pads and rotors (already ordered).
More Info:
I pulled everything apart and all physical components look OK. Brake lines are in amazingly good shape; no kinks or undue bends.
The caliper cylinders compressed without "too much" trouble, but required decent leverage once off the car - and the pins were a rusty mess (part of the problem)!
I checked the brake booster by pulling its vacuum line to see if the calipers let go. Unfortunately, my verdict is out on that test... I pulled the vacuum - which was holding a fair pressure - but found the wheel still didn't turn freely. The pickle is, I could turn it with some muscle, but it was still much harder to rotate than before these problems crept up.
Any help is appreciated!
Thanks
06-20-2007, 06:39 PM
#2
Rennlist Member
either your caliper is locked up or your brake line is collapsed and not letting fluid return to the resevoir. Open your bleeder and see if its easier to push the piston in - if so you have a collapsed line. if not, your caliper is sticking.
06-20-2007, 10:03 PM
#3
Burning Brakes
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Thanks, Dan.
That's the way I understand it, too. I just have a weird feeling that there's some other explanation.
We had some flooding on our road a couple months back. The rust got into the caliper pins pretty deeply. Could it really be so simple?
That's the way I understand it, too. I just have a weird feeling that there's some other explanation.
We had some flooding on our road a couple months back. The rust got into the caliper pins pretty deeply. Could it really be so simple?
06-23-2007, 09:29 PM
#4
If your pins are rusty that would definatly cause a binding issue, if the piston is moving in and out of the bore than your issue isnt with a frozen piston, its the pins. Now if you are having an issue with a frozen piston, on the front that can be caused by misadjusted rear drums (unsure if drum or disc in rear) causing the front calipers to work to hard. another problem could be the pistons may be "Phenolic" or a plastic like piston, they are very known for locking up.
Mark
Mark
