Right. If you start with A in the A-B-C sequence, isn't that starting highest though? Anyway, I was basically doing A-C-B using the logic of furthest away and work inside, just like the wheel order. That's worked fine over the years, but I'm definitely going to try the manual's sequence and hope for a little miracle.PatinaBeforePolish wrote:Robert,
The blue e12 factory manual section 34-00/2 says "Bleed all 3 bleeder screws A, B and C. Always bleed both lower pistons in sequence B-C." I interpret that as lowest to highest in elevation. (A is the upper screw, B inner and C outer)
I know we're drilling down to tiny details here - grease on the brake pads or rotors? Have you bedded the pads?
Braking balance
-
Robert Bondi
- Posts: 348
- Joined: Sun Jan 11, 2009 12:33 am
- Location: Austin, TX
Robert
77 530i
77 Euro 528
77 530i
77 Euro 528
-
Robert Bondi
- Posts: 348
- Joined: Sun Jan 11, 2009 12:33 am
- Location: Austin, TX
All good suggestions here, but I've unfortunately done all these for the most part.
Recall where I'm at. Both calipers are new BMW parts. Pulled the wheels and the pads after the test drive with left pulling while braking. Inspection with pedal action showed hydraulic action to the right caliper evenly distributed across all 4 pistons, but all hydraulic action delivered to just one piston on the left side. Effectively, that single left piston came out about 4x as far as any right side piston. That's the source of the pull in my mind.
I'm envisioning pulling off the boots on the left caliper and somehow
making sure lubrication is good for all on the left side, assuming the manual's bleed A-B-C sequence doesn't provide a magic solution.
Any other suggestions? I've got another left new caliper on the way as a contingency plan, but this sure is annoying.
Recall where I'm at. Both calipers are new BMW parts. Pulled the wheels and the pads after the test drive with left pulling while braking. Inspection with pedal action showed hydraulic action to the right caliper evenly distributed across all 4 pistons, but all hydraulic action delivered to just one piston on the left side. Effectively, that single left piston came out about 4x as far as any right side piston. That's the source of the pull in my mind.
I'm envisioning pulling off the boots on the left caliper and somehow
making sure lubrication is good for all on the left side, assuming the manual's bleed A-B-C sequence doesn't provide a magic solution.
Any other suggestions? I've got another left new caliper on the way as a contingency plan, but this sure is annoying.
Robert
77 530i
77 Euro 528
77 530i
77 Euro 528
-
PatinaBeforePolish
- Posts: 353
- Joined: Sun Jan 18, 2015 1:22 pm
- Location: Baltimore, Md.
Robert,
The factory manuals can sometimes be a little assumptive rather than literal. I interpret the manual as be sure to bleed all 3. It only specifies the B to C sequence so (my) common sense and experience say bleed B, C then A.
Anyway, bleed the hell out of them and hope you figure out why it's pulling. Please share any "ah ha!" moments.
Jon
The factory manuals can sometimes be a little assumptive rather than literal. I interpret the manual as be sure to bleed all 3. It only specifies the B to C sequence so (my) common sense and experience say bleed B, C then A.
Anyway, bleed the hell out of them and hope you figure out why it's pulling. Please share any "ah ha!" moments.
Jon
79 528i
76 530i - Stored since 1992, can it be brought back to life?
86 944- 2023 project
78 F150- Everyone needs a truck
76 530i - Stored since 1992, can it be brought back to life?
86 944- 2023 project
78 F150- Everyone needs a truck
Robert,
Get the piston extended to where it can be grabbed by pliers and rotated at the top, I do this first with the caliper still on the car because the hydraulic assistance of the brake pedal is so much easier. Then if you pull the caliper, split it, and pull all 4 pistons they can be cleaned. I use Kroil to help lube them for removal, it dissolves rust. Getting pistons out can be fun. Get a brake hone and chuck it up in your drill press and hone the bores. Use polishing paper to clean the pistons. lean out everything and Re-assemble and you should be good to go!
I've only done about 50 of these. Lube with new fluid on assembly. Be sure to properly orient the pistons in the bores.
You will be surprised at how dirty the inside likely is from water. Brake fluid attracts water.
Ron
Get the piston extended to where it can be grabbed by pliers and rotated at the top, I do this first with the caliper still on the car because the hydraulic assistance of the brake pedal is so much easier. Then if you pull the caliper, split it, and pull all 4 pistons they can be cleaned. I use Kroil to help lube them for removal, it dissolves rust. Getting pistons out can be fun. Get a brake hone and chuck it up in your drill press and hone the bores. Use polishing paper to clean the pistons. lean out everything and Re-assemble and you should be good to go!
I've only done about 50 of these. Lube with new fluid on assembly. Be sure to properly orient the pistons in the bores.
You will be surprised at how dirty the inside likely is from water. Brake fluid attracts water.
Ron
Ron Dwyer
Milwaukee, Wi
14 Audi A8L TDI
03 530i
08 F150 4X4
Milwaukee, Wi
14 Audi A8L TDI
03 530i
08 F150 4X4
-
Robert Bondi
- Posts: 348
- Joined: Sun Jan 11, 2009 12:33 am
- Location: Austin, TX
A follow-up on this thread.....
I essentially fixed the problem, although the reason for all the initial problems still really isn't clear. I simply bought another new left caliper.
I spent some additional time bench testing the new caliper. I pulled off the boots, lubricated the piston lateral surfaces with a little clean brake fluid, and used compressed air and small blocks of wood to ensure all pistons were free w/o blowing any pistons out of their bores. This time, all were free enough so that the wood wasn't necessary to block off the least resistant to make the most resistant piston move. There's still a slight left pull for the discriminating driver on serious braking, but this is much better than with the first new caliper.
Ron - That's excellent information if I ever need to rebuild a caliper. One critical point you overlooked is that the first problem caliper was also brand new, so old fluid collecting water and rusting things out inside wasn't the issue. I'm still not really sure what the problem is on that caliper.
The first problem left caliper was a new BMW part sourced through BavAuto. Given my trouble, I think I'll ask them to send me a caliper repair kit. I don't see any obvious reason why some bench testing and lubrication and a caliper repair kit can't get that first caliper in good working order too.
In summary, a possible heads-up to all to give your new/rebuilt calipers out of the box a closer look before putting everything together. I run DOT 5 and I got to basically go through three major brake bleeds and used about 8 qts. DOT 5 runs about $25-$30 a qt..........yeah, not a great feeling as you keep popping the seals off those bottles over and over.
I essentially fixed the problem, although the reason for all the initial problems still really isn't clear. I simply bought another new left caliper.
I spent some additional time bench testing the new caliper. I pulled off the boots, lubricated the piston lateral surfaces with a little clean brake fluid, and used compressed air and small blocks of wood to ensure all pistons were free w/o blowing any pistons out of their bores. This time, all were free enough so that the wood wasn't necessary to block off the least resistant to make the most resistant piston move. There's still a slight left pull for the discriminating driver on serious braking, but this is much better than with the first new caliper.
Ron - That's excellent information if I ever need to rebuild a caliper. One critical point you overlooked is that the first problem caliper was also brand new, so old fluid collecting water and rusting things out inside wasn't the issue. I'm still not really sure what the problem is on that caliper.
The first problem left caliper was a new BMW part sourced through BavAuto. Given my trouble, I think I'll ask them to send me a caliper repair kit. I don't see any obvious reason why some bench testing and lubrication and a caliper repair kit can't get that first caliper in good working order too.
In summary, a possible heads-up to all to give your new/rebuilt calipers out of the box a closer look before putting everything together. I run DOT 5 and I got to basically go through three major brake bleeds and used about 8 qts. DOT 5 runs about $25-$30 a qt..........yeah, not a great feeling as you keep popping the seals off those bottles over and over.
Robert
77 530i
77 Euro 528
77 530i
77 Euro 528
I should have read everyones post in detail first, my answers were a bit general. Glad that fixed the problem!
https://www.ecstuning.com/b-motive-part ... i4DUQ[url]
The power bleeder is a garage essential for these cars.
https://www.ecstuning.com/b-motive-part ... i4DUQ[url]
The power bleeder is a garage essential for these cars.
Ron Dwyer
Milwaukee, Wi
14 Audi A8L TDI
03 530i
08 F150 4X4
Milwaukee, Wi
14 Audi A8L TDI
03 530i
08 F150 4X4
-
PatinaBeforePolish
- Posts: 353
- Joined: Sun Jan 18, 2015 1:22 pm
- Location: Baltimore, Md.
Ron,
Good guidance here. But I thought I read somewhere that splitting the calipers is risky as the bolts are NLA in the event they're stripped. Correct? Or do you have a source for the bolts?
Jon
Good guidance here. But I thought I read somewhere that splitting the calipers is risky as the bolts are NLA in the event they're stripped. Correct? Or do you have a source for the bolts?
Jon
79 528i
76 530i - Stored since 1992, can it be brought back to life?
86 944- 2023 project
78 F150- Everyone needs a truck
76 530i - Stored since 1992, can it be brought back to life?
86 944- 2023 project
78 F150- Everyone needs a truck
I have never had an issue with bolts. If they break, consider it a message that they were close to toast. Look up Kroil and buy it and use it. Any bolt that is deemed to be corroded should be soaked for at least an hour or overnight with it on the nut end. It is likely a mix of a mild acid and a light oil to help draw it in. The stuff tears up my hands, wear gloves.
If the car is from the east, corroded, and old, get a rebuild caliper and let a rebuilder take the risk on the core. I don't sell fasteners, they are likely no better than grade 8 SAE or 8.8 metric. If you do break a bolt, replacements are readily available, if the car is needed to drive to school tomorrow, that is what we call a risk analysis.
Bottom line, brakes are what saves your ass from rear ending a dump truck, or a wheel barrow full of puppies. Stopping is more important than accelerating. Rebuilding calipers over the last 40 years is what makes giving advice challenging. I know what I'd be willing to call acceptable if I was working on it.
If the car is from the east, corroded, and old, get a rebuild caliper and let a rebuilder take the risk on the core. I don't sell fasteners, they are likely no better than grade 8 SAE or 8.8 metric. If you do break a bolt, replacements are readily available, if the car is needed to drive to school tomorrow, that is what we call a risk analysis.
Bottom line, brakes are what saves your ass from rear ending a dump truck, or a wheel barrow full of puppies. Stopping is more important than accelerating. Rebuilding calipers over the last 40 years is what makes giving advice challenging. I know what I'd be willing to call acceptable if I was working on it.
Ron Dwyer
Milwaukee, Wi
14 Audi A8L TDI
03 530i
08 F150 4X4
Milwaukee, Wi
14 Audi A8L TDI
03 530i
08 F150 4X4
Being I was original poster... Here's what I did (learned)
I ordered pads, hardware, and both rear caliper re build kits. ~50$ total shipped.
My car was from Boston area, and came with a full set of studded snow tires, so yes, it's seen salt and snow. Some things are really rusty, however the body is in great shape.
However I started taking the pads out and before removing the caliper tried to see if braking pressure was enough to pop the Pistons loose. No. So I took the caliper right off split it, (I soaked the Allen bolts with pb blaster over night) and they came off quite easily with the 10/11mm tube tool in the toolbox. I then used my impact hammer and a 9/16s socket to push the Pistons in all the way, yes they moved! But on the second piston my socket cracked and allowed my hammer to hit the piston. It made a hole in it.
So after frantically trying to source a replacement caliper, I decided to test my welding skills. Put a little bead right in the hole I made. And voila the piston is sealed. So I put it back on the car to try brake pressure pushing the Pistons and still to no avail. So I pulled the caliper back off and filled it with PB blaster completely full. Haha
At this point I was a little disappointed, never had this much trouble rebuilding a caliper in my life. So I started cross referencing part numbers and I found some rebuilds! I'll share
Cardone 19-431 Remanufactured Import Friction Ready (Unloaded) Brake Caliper (left rear)
Cardone 19-430 Remanufactured Import Friction Ready (Unloaded) Brake Caliper (right rear) Cardone 19-430 Remanufactured Import Friction Ready (Unloaded) Brake Caliper
Only three left rears left and 13 right rears. I also did find more on other sites, just gotta cross reference the part numbers. I know I wouldn't pay 465$ for an oem BMW one... 50$ each is a much better deal.
So hopefully this fixes my break bias problem (my left rear was completely frozen up both Pistons.. But the right rear seems to be working somewhat so maybe I'll be able to rebuild that one) and yes I would not drive on a welded piston I only wanted to extract it to see if I could...
I ordered pads, hardware, and both rear caliper re build kits. ~50$ total shipped.
My car was from Boston area, and came with a full set of studded snow tires, so yes, it's seen salt and snow. Some things are really rusty, however the body is in great shape.
However I started taking the pads out and before removing the caliper tried to see if braking pressure was enough to pop the Pistons loose. No. So I took the caliper right off split it, (I soaked the Allen bolts with pb blaster over night) and they came off quite easily with the 10/11mm tube tool in the toolbox. I then used my impact hammer and a 9/16s socket to push the Pistons in all the way, yes they moved! But on the second piston my socket cracked and allowed my hammer to hit the piston. It made a hole in it.
So after frantically trying to source a replacement caliper, I decided to test my welding skills. Put a little bead right in the hole I made. And voila the piston is sealed. So I put it back on the car to try brake pressure pushing the Pistons and still to no avail. So I pulled the caliper back off and filled it with PB blaster completely full. Haha
At this point I was a little disappointed, never had this much trouble rebuilding a caliper in my life. So I started cross referencing part numbers and I found some rebuilds! I'll share
Cardone 19-431 Remanufactured Import Friction Ready (Unloaded) Brake Caliper (left rear)
Cardone 19-430 Remanufactured Import Friction Ready (Unloaded) Brake Caliper (right rear) Cardone 19-430 Remanufactured Import Friction Ready (Unloaded) Brake Caliper
Only three left rears left and 13 right rears. I also did find more on other sites, just gotta cross reference the part numbers. I know I wouldn't pay 465$ for an oem BMW one... 50$ each is a much better deal.
So hopefully this fixes my break bias problem (my left rear was completely frozen up both Pistons.. But the right rear seems to be working somewhat so maybe I'll be able to rebuild that one) and yes I would not drive on a welded piston I only wanted to extract it to see if I could...
81 528ia black - semi-dd
92 BMW K75 - dualsport/cruiser
03 Chevy Silverado 1500hd - tow-rig/bad weather
84 Toyota celica supra - drift/autox/hillclimb duty
92 BMW K75 - dualsport/cruiser
03 Chevy Silverado 1500hd - tow-rig/bad weather
84 Toyota celica supra - drift/autox/hillclimb duty
OK... New calipers are on, new pads... I just reused the discs, scuffed them up with a die grinder and Brillo pad. And went out for a few "emergency" stops... Still no locking in the rear... I can see where the pads have seated in and scuffed the rotors... So now back to my original issue of not enough pressure to the rear calipers. Lol
Fronts lock up really easily...
Fronts lock up really easily...
81 528ia black - semi-dd
92 BMW K75 - dualsport/cruiser
03 Chevy Silverado 1500hd - tow-rig/bad weather
84 Toyota celica supra - drift/autox/hillclimb duty
92 BMW K75 - dualsport/cruiser
03 Chevy Silverado 1500hd - tow-rig/bad weather
84 Toyota celica supra - drift/autox/hillclimb duty