And if so, how hard was it?

I've had a shop do it for me previously, but it's time again, and I think I'd like to save some money and do it myself. I'll replace the pistons while I'm at it: after four years, 67 track days, and 6,000 track miles (36,000 total miles), I think it's about time.

So what's involved? Any special tools? Any difficult or tricky aspects? How would you rate its difficulty? (BTW, I don't have a garage, so I'll be doing the work in my kitchen, if that makes any difference.)

Has anyone posted a step-by-step description of the procedure? I searched, but didn't find anyone here who had even said they had done it.

I did find plenty about how to paint calipers, which is good, since I'm going to do that at the same time. Mine have been deep chocolate colored for a couple of years.

Thanks for your advice.

 

I dont believe you have to rebuild your caliper unless they are locked or leaking of some sort.

 

After a year's worth of track days (17 this year), many of the seals and dust boots are cracked and/or missing. They need rebuilding, trust me.

 

I can't vouch for the particulars on the Brembo's, but the very similar Stoptech's are pretty easy. You'll need compressed air to push the pistons out, a small bar clamp (the little trigger/ratchet style with rubber covers on the pads), and a block of plywood to hold the pistons in on the opposite side you're working on. A small or jewelers flat blade screwdriver and/or awl will be needed to poke/pull the seals out of the grooves. Also, a can of the best brake cleaner you can find.

On the rear, start by removing the brake line, clamping a piston back in the bore and stick a catch rag between it and the piston you're going to blow out. Use an air gun on the brake line port and feed just enough pressure to move the piston out of the bore (too much pressure and the piston will bounce off the clamp and possibly get nicked).

The dust boots should be good and dried up, so they'll come out easy with a little careful prying. You'll see the seal in the groove about 1/4" inside the bore. Carefully stab it without scratching the bore, pull it out of the groove and remove it from the caliper. Clean everything up with brake cleaner, paying particular attention to the area between the dust boot and the seal. That's where the most abrasive baked on brake dust will be. Once everything's cleaned up and inspected, smear a little brake fluid around the seal groove to ease installation. Pinch the seal in your fingers and press it into the groove, making sure that it's seated evenly around the whole circumference. Smear a little brake fluid around the seal after it's installed too.

Install the dust boot on the cleaned up/new piston before pressing back into the caliper. Start it by hand, then use the clamp and block of wood to completely compress the piston back into the bore and seat the dust boot at the same time.

Repeat another 11 times and you're done! It takes a couple of hours but it's easy work as long as you don't try to take any shortcuts (like trying to hold a piston in by hand while you blow the opposite one out). I pulled, cleaned and inspected all mine before ordering up the seal kit. Don't do that. It's a waste of time doing everything twice, and you'll increase the likelyhood of nicking a piston. Just order up the kit and be done with it.

Good Luck!

 

Tim: thanks for the details.

What if I don't have a source of compressed air?

Also, note that I expect I'll be replacing the pistons, and removing the calipers completely to work on them (and paint them) indoors. Does that make a difference to anything you've described?

 

I only have my own limited experience to draw on, but I think that trying to pull the pistons out (pliers?) will be more trouble than necessary. I have a little Cheapo Depot homeowner compressor with a built in regulator, hose & attachments that cost about $100.00 or so. I'm sure you could use a smaller/cheaper unit too, as long as it will do up to 60-80 PSI there's certainly not much flow required.

I did assume you'd have the calipers removed, just wanted to mention you should yank the flex lines too. Another thing with compressed air is that you'll get some fluid & mist blowby when the pistons come out of the bores. It's fairly messy. Make sure you cover your nice table with something first. I bet Brembo pistons are expensive and you probably don't need them (Depends how long you ran with disintegrated dust boots). Mine were all fine, just needed to be cleaned up right at the dust boot groove.

 

Yeah, I thought it could be a good excuse to buy a new toy... err...tool!

As for replacing the pistons, it may not be necessary, but with all the track time I've put on the car, and since I didn't pay as much attention to the brakes in the first year or two as I should have, it's probably worth it, if only for the peace of mind. It'll cost about $300 just for the pistons, on top of about $150-200 for the rebuild kits.

When you say "yank the flex lines" do you mean replace them? I have stainless steel, but they're almost four years old now. I was going to inspect them, but didn't think I'd have to replace them yet. Any advice there?

Thanks again.

 

Sorry, yank = remove. It's tough to hold the caliper, flex line, and air gun with only 2 hands. Do it the easy way by removing the flex line, just be sure that you replace the crush washers when you re-install it. I'm sure the flex lines will be fine with a visual inspection.

 

I also recently rebuilt my stoptechs to put in knockback springs after a similar number of track days as you. I had no idea what I was doing either but once you get them off the car, it is very intuitive. You will need a source of compressed air. I supposed if you really want to go the 'workman' way, you could use a bicycle pump and have a helper to give one good push, but why not use this as an excuse to buy a new compressor You only need a couple pounds of air to get the pistons out (maybe 5 lbs). My first piston came out like a cannonball with my regulator set at 30lbs.
I will say that my inner seals were in perfect shape and really didn't need replacing. One of those, 'while I was in there things'. I don't anticipate ever needing to rebuild them again.

 

How do you like the knockback springs, Dave? I've been having knockback since Day 1, but I've gotten used to it. And since the car is a daily driver, not a dedicated track car, I've assumed that knockback springs would unduly decrease pad life for a minor on-track benefit. But, since I'll be in there....

Have you seen much extra pad wear?

 

I think the knockback springs are great! I had the same concerns as you and held off for the longest time because it's my street car. So far, I've seen none of the disadvantages I thought I would. I wish I had put them on the day I bought my stoptechs two years ago.
It's probably too early to tell if I'll have any accelarated pad wear but the solid pedal makes it worth it to me. Plus street pads are cheap and last me 3 years at a time.
The only think I haven't been able to test is for fade due to drag induced heat on a hot summer day, but I think I'd rather have predicatable fade than knockback that can rear its ugly head randomly.

 

Interesting. I needed a lot more pressure than that, and in retrospect should have replaced the dust boots only. I did the rebuild based on dried up/split dust seals and the suggestion of the manufacturer when I called to get replacement rotors.

 

Well, maybe I'll consider knockback springs, too. Do you know if anyone makes them for the Brembos, or if I could use the Stoptech springs?

Do you switch from street to track pads for every event? I'm lazy, and don't bother. I just leave the track pads in during the season. Do you think that would be a problem? Do the springs make track pads squeak?

 

I do switch pads for track events. Not sure if the springs would make track pads squeak but you might run the risk of faster rotor wear. The springs do cause a lot more brake pad dust to gather on the wheels. I guess that's the big downside.

 

Pretty good advice --Be very careful with the compressed air on the pistions, I use a block of wood as a stop.

I buy Brake component Assy Lube from Napa, It is Compatable with all fluids because actually it IS fluid. It has the consistancy of honey and is super slippery, really helps on reassembly so u dont tear ur boots

 

were could one buy the knockback springs?

 

any body?

 

Any dealer that carries stopetech or AP Racing products can get them. I got the AP 4lb large diameter springs for the fronts. They seem to be sufficient for me.

 

thanks.

 

I don't have a clue on what you guys are talking about but its so damn facinating reading it.