E9 brake calipers

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2260477

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I am finding it difficult to source brake calipers for vented rotors. There are companies offering rebuilt calipers. When I fill out the online order forms, they apologize that no longer in stock. I read that 1978-1982 633 CSi calipers will fit, can anyone confirm this?
 
According to realoem.com, 34111101859 is the left caliper, 34111101860 is the right caliper, both front and complete less pads.

Put those part numbers in the realoem search and it comes up that only the 3.0Si that shared those calipers. They are quoted $433 each.

That said there are supposedly other calipers that fit. From my notes, "Front: for vented rotors, later E12 calipers will bolt-on. Also, 76-81 6-series front calipers should bolt on...but beware, prices for 6-series coupes are often worse than for E9 coupes. Rear Vented: 6-series 77-81, though these probably aren't cheaper than E9 calipers.

It is left as an exercise to the reader to look up those caliper part numbers, then use realoem's Search function to see what cars they were used with.
 
If you really want to restore calipers the right way

you should send them to someone who can sleeve them in SS and provide new SS pistons. Places like SSBC, Apple Hydraulics, etc. can do it for you. Preferably, you should also switch over to Silicon brake fluid (DOT5) so your hydraulic system stops rusting from the inside.

It's a lot more money as they charge by the hole (our calipers have 4 holes so that's >$200 each), but cars that don't get driven much are much more prone to hydraulic corrosion because most owners don't flush the hydraulic fluid every year or other year and because the parts don't see enough use. I'd also sleeve the brake MC, and clutch MC/Slave in SS as well. So, we're talking around $1600 to redo all that stuff, but with a hard line flush you're starting out better than new parts and are in the perfect situation to switch to DOT 5.

And, you'll never have to deal with hydraulic problems again. Seems like a fair return on investment IMHO. Yes, I'll eventually do this to my coupe when it goes in for a complete body job.

John
 
bfeng said:
you should send them to someone who can sleeve them in SS and provide new SS pistons. Places like SSBC, Apple Hydraulics, etc. can do it for you. Preferably, you should also switch over to Silicon brake fluid (DOT5) so your hydraulic system stops rusting from the inside.

It's a lot more money as they charge by the hole (our calipers have 4 holes so that's >$200 each), but cars that don't get driven much are much more prone to hydraulic corrosion because most owners don't flush the hydraulic fluid every year or other year and because the parts don't see enough use. I'd also sleeve the brake MC, and clutch MC/Slave in SS as well. So, we're talking around $1600 to redo all that stuff, but with a hard line flush you're starting out better than new parts and are in the perfect situation to switch to DOT 5.

And, you'll never have to deal with hydraulic problems again. Seems like a fair return on investment IMHO. Yes, I'll eventually do this to my coupe when it goes in for a complete body job.

John
Click to expand...

+1 for DOT 5 for the older vehicles. Never worry about blistering paint and pitted sleeves again!!
 
brake calipers

Thanks to all who posted replies with good info and advice. The pistons moved back into their cylinders on all 4 calipers.

I removed the dust rubbers and retainer clips, soaked the pistons for 2 days with rust buster liquid and put the calipers back on the wheels. I am going to try and see if the brake fluid pressure will push the pistons out so that I can see the condition the pistons and cylinder walls. Maybe good enough to rebuild.
 
From the net...


Brake system contamination
The single most common brake system failure caused by a contaminant is swelling of the rubber components (piston seals etc.) due to the introduction of petroleum based products (motor oil, power steering fluid, mineral oil etc.) A small amount is enough to do major damage. Flushing with mineral spirits is enough to cause a complete system failure in a short time. I suspect this is what has happened when some BMW owners changed to DOT 5 (and then assumed that silicone caused the problem). Flushing with alcohol also causes problems. BMW brake systems should be flushed only with DOT 3 or 4.

If silicone is introduced into an older brake system, the silicone will latch unto the sludge generated by gradual component deterioration and create a gelatin like goop which will attract more crud and eventually plug up metering orifices or cause pistons to stick. If you have already changed to DOT 5, don't compound your initial mistake and change back. Silicone is very tenacious stuff and you will never get it all out of your system. Just change the fluid regularly. For those who race using silicone fluid, I recommend that you crack the bleed screws before each racing session to insure that there is no water in the calipers.
 
Changing to DOT5

sfdon said:
From the net...


Brake system contamination(snip)
Click to expand...

Thanks for the extra knowledge, Don. I should have mentioned that it's a good idea to change the soft lines for new when switching to DOT5.

WRT fixing sticky caliper pistons: I've had good luck cleaning things up with a bit of metal etch to eliminate the rust (phosphoric acid) followed by a light touch with 2000 grit sand paper. But, I've also found that periods of inactivity are likely to cause those same pistons to stick again in the future .

John
 
but but but... doesn't phosphoric acid convert ferrous rust to iron phosphate, rather than somehow making the rust "disappear"? Methinks you gots to physically remove the rust via wire wheel, wet/dry sandpaper, emery cloth, buffing, whatever. Even then you are stuck with pitted metal.
 
brake calipers

I connected the brake feed lines to the calipers and bled the system. When I applied the brakes (with a piece of wood between in place of the rotors, and all pistons came out. Cleaned the pistons and cylinders with emory cloth and washed everything thoroughly with brake cleaner. Installed rebuild kits and the fronts are back in action.

The rear calipers were a bit more stubborn but I got them freed up and cleaned. The pistons were stuck on a bit of crud build-up on the outer edge of the cylinders.
 
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