how to know when to replace calipers?
-
Guest
i've got this annoying scraping kind of hiss coming from the back wheels (can you tell i hate strange noises?) when i brake, the pads needed replacing, i did that but still have the same sound..i also have new rotors... is it safe to say its the calipers? i'm pretty sure they have never been changed although i'm not sure. I'm also not sure how a caliper 'goes bad'
-
Aaron from Aus
- Posts: 559
- Joined: Feb 12, 2006 12:00 PM
- Location: Australia
- Contact:
Take off the wheel and take a look.
Is it leaking brake fluid?
Are the bolts to mounting bracket tight ? (i have had this happen)
try to bleed it, it the bleeder screw is blocked up they probably need to be pulled apart and cleaned..even rebuilt with new seals.
There really is not much that can go wrong with them, apart from seals and a good clean cant fix.
The other issue could be bloated/damaged brake line to the caliper.
Is it leaking brake fluid?
Are the bolts to mounting bracket tight ? (i have had this happen)
try to bleed it, it the bleeder screw is blocked up they probably need to be pulled apart and cleaned..even rebuilt with new seals.
There really is not much that can go wrong with them, apart from seals and a good clean cant fix.
The other issue could be bloated/damaged brake line to the caliper.
-
Guest
-
Tammer in Philly
- Posts: 10719
- Joined: Feb 12, 2006 12:00 PM
- Location: CHI, IL
[QUOTE="tacm"]Sound like the calipers are dragging [/QUOTE]
A dragging caliper will make some noise when NOT braking, pushing the pads against the rotor should make it stop. You'll also get uneven brake pad wear on that wheel (the inside pad will wear very quickly). You may notice some pull to that side when braking, as that pad could grip faster than the others.
Calipers don't need replacing, but they do need rebuilding from time to time (more often for tracked cars that see very high brake temps). The procedure is pretty simple. I'll type it up here (I posted this on the old board a month or so back).
For single-piston or multi-piston calipers:
1) Extract pistons. This is tougher with multiple pistons, 'cause you have to get them all out at the same time. Use a block of wood to block their exit and hit them with compressed air (in the bleeder hole) to push them all up to "flush", then little bursts of air to ease them out, blocking ones that get ahead. As with all pistons, when using air they will pop out with some force--be careful and use a soft rag over something to catch 'em! Check P-car boards for more tips on removing multiple pistons.
2) The rest of the job is straightforward. Clean up the bores with very fine sandpaper, wash w/ brake fluid, replace all seals, and re-install. Getting the dust boots back on can be a little bit of a PITA the first time, but a little patience goes a long way. The fourth caliper will take you about 1/3 as long as the first.
3) Lube bores/seals* and reinstall pistons. Be very careful to get them aligned properly; they will go in with firm but not forceful pushing if properly aligned. When the dust boots go in, you'll feel some extra resistance, but they should seat without excessive force. If they "catch", pop 'em out and start over; you don't want to score the bore.
*There are different schools of thought as to re-assembly lube. Some say just wash it all in brake fluid, wet the seals and bore, and shove the piston in. That was what I did. Others have recommended syl-glide or a similar silicone lubricant.
A dragging caliper will make some noise when NOT braking, pushing the pads against the rotor should make it stop. You'll also get uneven brake pad wear on that wheel (the inside pad will wear very quickly). You may notice some pull to that side when braking, as that pad could grip faster than the others.
Calipers don't need replacing, but they do need rebuilding from time to time (more often for tracked cars that see very high brake temps). The procedure is pretty simple. I'll type it up here (I posted this on the old board a month or so back).
For single-piston or multi-piston calipers:
1) Extract pistons. This is tougher with multiple pistons, 'cause you have to get them all out at the same time. Use a block of wood to block their exit and hit them with compressed air (in the bleeder hole) to push them all up to "flush", then little bursts of air to ease them out, blocking ones that get ahead. As with all pistons, when using air they will pop out with some force--be careful and use a soft rag over something to catch 'em! Check P-car boards for more tips on removing multiple pistons.
2) The rest of the job is straightforward. Clean up the bores with very fine sandpaper, wash w/ brake fluid, replace all seals, and re-install. Getting the dust boots back on can be a little bit of a PITA the first time, but a little patience goes a long way. The fourth caliper will take you about 1/3 as long as the first.
3) Lube bores/seals* and reinstall pistons. Be very careful to get them aligned properly; they will go in with firm but not forceful pushing if properly aligned. When the dust boots go in, you'll feel some extra resistance, but they should seat without excessive force. If they "catch", pop 'em out and start over; you don't want to score the bore.
*There are different schools of thought as to re-assembly lube. Some say just wash it all in brake fluid, wet the seals and bore, and shove the piston in. That was what I did. Others have recommended syl-glide or a similar silicone lubricant.