Page 1 of 16 Bimmerforums - The Ultimate BMW Forum > Bimmerforums - BMW Car/Model Specific > 3 series (E21, E30, E36, E46, E9x, F30) > 1983-1991 (E30) DIY: Bake Caliper Rebuild Welcome, bdbernard. You last visited: Yesterday at 04:16 PM Private Messages: Unread 0, Total 82. User CP FAQ Calendar New Posts Search Quick Links Log Out TireRack Garage Homepage Supporting Vendors Online Store Photo Gallery Forum Rules Advertising Ads by Google Autoteile BMW E30 BMW Repair BMW Engine Caliper 1983-1991 (E30) (1983-1991) Born from the sporty character of the 2002 and the sharp design lines of the E21, the E30 was a blend of the best of BMW's heritage. The second generation 3 Series provided a thrilling driving experience that used the best technology available. Thread Tools Search this Thread 07-20-2008, 09:00 PM knotcher #1 Join Date: Dec 2006 Location: Fuquay Varina Cars: 96 328i; 89 325i Posts: 71 DIY: Bake Caliper Rebuild I'm in the process of building an e30 race car. i haven't put up any good tech yet so i thought i'd give it a shot. feel free to read about the build. 1. start with a clean work surface
Page 2 of 16 2. clean your bench and lay out your rebuild kit(s)
Page 3 of 16 3. on the rear calipers, remove the retaining ring 3. pull the ring and boot off
Page 4 of 16 4. if you have compressed air, shoot a little into the brake line hole. be careful as the piston will come out pretty quick so stick a rag or a block of wood in between the piston and the caliper so that it doesn't do any damage. if you don't have compressed air, you can use a bike pump with the cone nozzel. 5. after you get the piston out, pull out the inner seal careful not to scratch the wall of the caliper bore.
Page 5 of 16 6. clean out all the nasty stuff with brake clean and a toothbrush (nothing metal, so you don't scratch the walls).
Page 6 of 16 7. so now it's time to put it all back together. soak your inner seals in clean brake oil. 8. fit the new inner seal in it's slot and then stretch the boot over the piston as here.
Page 7 of 16 9. spread some brake fluid on the piston and bore walls and carefully push the piston back in...you should be able to do it with just your hands...if you get stuck, take it out and try again...don't get frustrated if it takes you a couple of tries. 10. put the retaining ring back on and you're all set.
Page 8 of 16 10. the fronts are a little harder than the rears...pull the boot over the piston like this
Page 9 of 16 11. tuck the boot into the slot in the caliper like this...it's hard...take your time and it helps to lube it all up with brake fluid. 12. push the piston in until the front of the boot slides into it's own slot.
Page 10 of 16 Last edited by knotcher; 07-21-2008 at 08:25 AM.. 07-20-2008, 09:09 PM kishg E30 fan #2 Join Date: Apr 2005 Location: NJ Cars: too many bmws Posts: 9,423 nice write up tks. i need to do this on my track car. are you building a spec e30 car? '91 SpecE30 #523 '03 540i/6 M-Sport '00 F-350 Dually BMWCCA #360858 NASA # 128290 My Track Schedule 07-20-2008, 09:17 PM knotcher #3 Join Date: Dec 2006 Location: Fuquay Varina Cars: 96 328i; 89 325i Posts: 71 Quote: Originally Posted by kishg nice write up tks. i need to do this on my track car. are you building a spec e30 car?
Page 11 of 16 not to the letter but it will be easy to convert to spec e30 when it's all done 07-20-2008, 09:24 PM kishg E30 fan #4 Join Date: Apr 2005 Location: NJ Cars: too many bmws Posts: 9,423 be sure to post up pics as you go along.. planning to convert mine to meet spec e30 rules sometime in the winter. '91 SpecE30 #523 '03 540i/6 M-Sport '00 F-350 Dually BMWCCA #360858 NASA # 128290 My Track Schedule 07-20-2008, 11:26 PM justinblec #5 Join Date: Sep 2007 Location: Baton Rouge Cars: 1995 M3 Posts: 536 Feedback Score: 7 reviews, 100% As a note to step 4; put a wooden board betwen the piston and the caliper to prevent the piston from shooting out. Otherwise if you're using compressed air and too much, the piston could fly across the room and hit someone or something. I had to use 150psi to get mine out. Don't want anyone getting injured. Also, do you guys like to use synthetic caliper grease on the cylinder? I did to prevent any rust between the bore/piston contact area BEYOND the internal seal, where water and air would be attracted by brake fluid. 07-21-2008, 12:16 AM indybeamer2008 #6 Join Date: Jul 2008 Location: Indianapolis, Indiana Cars: '89 325is Posts: 10 Nice write up for sure! 07-21-2008, 12:24 AM tjmonsen5 Mad Pwnage y0! #7 Join Date: Aug 2005 Location: Crystal Lake, Illinois Cars: 86 325e Baur, 87 325is Posts: 3,235 Feedback Score: 2 reviews, 100% good write up! maybe ill do this when i do my brakes on me new e30!
Page 12 of 16 07-21-2008, 02:21 AM bmwlover0725 #8 Join Date: Sep 2006 Location: Endwell, New York Cars: 93' 325is-99' Z3 2.5 Posts: 2,631 I've been putting this off for over a year since my brakes still work decent. rebuild kit will be ordered with timing belt next pelicanparts purchase. good writeup, subscribed. 07-21-2008, 08:22 AM knotcher #9 Join Date: Dec 2006 Location: Fuquay Varina Cars: 96 328i; 89 325i Posts: 71 Quote: Originally Posted by justinblec As a note to step 4; put a wooden board betwen the piston and the caliper to prevent the piston from shooting out. Otherwise if you're using compressed air and too much, the piston could fly across the room and hit someone or something. I had to use 150psi to get mine out. Don't want anyone getting injured. Also, do you guys like to use synthetic caliper grease on the cylinder? I did to prevent any rust between the bore/piston contact area
Page 13 of 16 BEYOND the internal seal, where water and air would be attracted by brake fluid. yeah...good point...i used a shop rag instead of a block of wood and it sufficiently softened the blow. i'll add that to the write up. i can't believe you needed 150psi...i think i used 10 or 15 at the most...your piston must have been seized on or something. i don't know about the caliper grease...seems like you would only want brake fluid there an nothing else. 07-21-2008, 10:13 AM E30 Groupie #10 Join Date: Jan 2006 Location: Milwaukie, Oregon Cars: 86 325es4 & 94 540iTa Posts: 1,258 Feedback Score: 1 reviews, 100% I have to give you guys credit for taking the time to post these up for those that dont know. I always intend to, but never actually end up taking all the pics etc. I get too into my work. x2 on the caliper grease. I usually keep that away from any BMW system. 08-27-2009, 07:46 PM JoeliusCeasar #11 Join Date: Jun 2009 Location: CNY Cars: 1991 318i E30 M42 Posts: 86 HELP!! I got the pistons out cleaned the calipers nicely and painted them. the pistons will slide in with the inner seal, but not when I put the dust seal on I don't know how in the world I can get them together again. Thanks if anyone looked, but the dust seals were too thick and that was the problem. Last edited by JoeliusCeasar; 08-27-2009 at 08:55 PM.. Reason: Problem solved. 08-27-2009, 10:59 PM #12 Ranger1 Join Date: Jul 2007 Location: Savannah, GA Cars: SpecE30, E36, F150 Tow Posts: 3,409
Page 14 of 16 Voice of reason Feedback Score: 1 reviews, 100% Well done knotcher. Pelican got the process of putting the boot on, wrong. If you'd a ready their book, you'd a spent 2hrs struggling to do it their way. Instead it looks like you figured it out yourself without going off on a wild goose chase like I did. http://www.gress.org/home/cars/track...liperboots.htm Porsche Certified Performance Driving Instructor www.gress.org Last edited by Ranger1; 08-27-2009 at 11:01 PM.. 08-28-2009, 12:29 AM djb2 #13 Join Date: Sep 2006 Location: Annapolis MD Cars: 1987 325is, Z3 Posts: 2,609 Quote: Originally Posted by knotcher i can't believe you needed 150psi...i think i used 10 or 15 at the most...your piston must have been seized on or something. Well, you wouldn't be rebuilding the caliper if it worked perfectly. I was playing with a problem Miata caliper last weekend. It took a fair build-up of pressure before the piston would come out, and then it would spit out really hard with a boom. I had to do this a few times because the piston would jam when I tried to reassemble it. Once I cleaned up the ridge between the pressure seal and dust boot it both went in smoothly, and came out gradually with just a little 'pop'. That's the difference between real life broken parts and classroom practice. 10-17-2010, 01:58 PM #14 bmwpower Join Date: Aug 2002 Location: NJ Cars: 99 M3, 90 535iA, 89 325is
Page 15 of 16 garage junkie Posts: 3,773 Feedback Score: 3 reviews, 100% Ok, couple of questions: (1) Since the piston never makes contact with the bore (or does it?), why do you need to be extra careful when cleaning the bore? The piston only contacts the seal lining the bore, correct? (2) Is it ok to clean up the piston with scotchbrite? Light cleaning to remove dried on gunk that may affect sealing properties. bmwpower / bmwcca 147895 / 99 M3 / 90 535i / 89 325is track project 10-17-2010, 02:53 PM Macktheknife Blinding... with SCIENCE #15 Join Date: Apr 2006 Location: Urbana, IL Cars: 1987 325 Posts: 1,210 Great write-up, I coulda used this when I did a rebuild on one of my front calipers last year. http://www.flickr.com/photos/mdeegan/ Bookmarks Digg del.icio.us Facebook MySpace Quick Reply Message:
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