Hey guys,

I have purchased a used set of brembo brakes here about a year ago for swapping to my 4th gen eclipse. They worked fine ever since the swap until 3 days ago when I decided to install SS line, and taken them all off to repaint. Here are the mistakes I made; when I brought the calipers in for sandblasting, bits of sand entered the caliper via where the nipples used to be but I believe flushing got majority of them out. Also, I accidentally let the master cylinder ran dry due to one hose being inproperly plugged when I was focusing on repainting the calipers. Here are my issues, the rear calipers bleeded fine but I broke a dustboot on 1 piston and will need to rebuild that piston so no worries. The front however, are having bleeding issues. The outside nipples for both front calipers have very limited fluid coming out when bleeding. The insides nipples are ok. Also, I found out both calipers' outside nipple sides 2 pistons arent moving much at all. I have done some search here and concluded maybe seized pistons but having very limited brake fluid coming out is strange. I got a mitsu tech to bleed again for me this afternoon and the brake pedal when car's off is very stiff just like before but when the engines running, the pedal feels a little mushy but the car still stops great and there's no brake dragging. I have done 2-3 hard stop to activate ABS prior to letting the mitsu tech flush the entire system. What gives?

 

They are now pretty paperweights

 

Well if that's the case, is there any way I can save the calipers? The inside nipples two pistons are still working just the outside is strange. When I first put them back to flush, the fluid comes out with tiny bit of sand but as I flush more and more, the fluid is clean and free of air or anything else. Can a simple rebuild and clean up of the internal make them work again?

 

Need more advise and opinions guys! Please help me out! I just took off the wheel and check the outer 2 pistons and can confirmed that they're seized. I'm going to remove the pistons and the dustboot and completely clean the inside and get rid of any sand if there's any. I should be able to get the pistons to work again if nothing is damaged right? is there anything else I need to know?

 

Sounds like there is some debris (or sand) in the tube going between the two halves of the caliper. Take it off, take out all pistons and seals and get some air pressure into that tube (runs along the bottom of the caliper, opposite where the bleed screws are).

Worst case take off that tube (and replace it) and clean out the holes beyond where the tube attaches into the caliper body. Pipe cleaners can be your friend in this application.

Careful inspection and replacement of assorted seals and/or pistons might be in order. Look for any scratching in the piston bores and on the pistons themselves. Repair/replace as needed.

I do not recommend taking the two caliper halves apart. Nothing to be gained from that.

 

Thanks alot for the help! I wouldn't think the pistons bore or anything are scratched because the pistons never even work when I put it back. I do suspect that the pistons were seized before I even taken them off already. Say if the seals and dustboots are actually fine, can I re-use them? Thanks again.

 

Yes. If there's no tears, nicks, etc in the seals they're fine to reuse. Soak them in brake fluid for lube and re-assemble. The dust boots are less critical. Assorted tool companies make dull, rounded-tip brass picks just for getting seals out of piston bores without nicking them. If you're talented, you should be able to squeeze a section up enough to get a q-tip behind it then gently pull them out with your fingers. Nothing pointed or sharp.

You're gonna have to find a special way to get the "stuck" pistons out since they're not moving. If you can pull them out by hand (grabbing onto the dust boot lip groove, for example) then do so. Otherwise you might have to put some compressed air into the bleeder screw hole. Put some various thickness wooden blocks between the caliper halves [where the pads would go] for that exercise. About 20 PSIG - that should be enough to move the pistons out. If you use full shop pressure, 125+ PSIG, then expect to hear a really loud pop and see wood splinters. KEEP YOUR fingers out of the way!! It's fun, but messy. Remember there's still some brake fluid in there.

I expect the pistons to be hard anodized so do not scratch them.

 

Thank you so much sir for all the info. I will be doing the rebuild sometimes this weekend. If you don't mind I'll come back with questions If any comes up

 

No prob. I should be close to the computer most of Saturday. Sun morn and early aftn I'm working the local SCCA solo (I'm a safety steward) so no Internet access then.

 

You done yet?

 

I'm not dont yet as I'm waiting for 1 replacement dustboot but I did find out the problem. The rear calipers like I said were just fine besides 1 cracked boot so that's taken care of. The front calipers issue turned out exactly sand clogging. Both side had a chunk of sand stuck right below the outer nipple. Compressed air couldnt even push them out so I had to use some small stick and push it out myself. I checked other nipples and pistons, there's nothing clogging. I guess all the sand was pushed to the outer nipple when I try to bleed. I will make sure I give the sandblasting guy a hell when I have a chance later on. The calipers should work just like before again! and none of the boots, seals, pistons were damaged so I'm really glad. Thanks again for the help!

 

Party On, Wayne!