E86 Z4M- Rear Brake Callipers Needed

[_Paclunch]

Does anyone have two rear brake callipers I could, borrow, buy, or know where I can get some?
This is for the Z4M, I've scoured the web and they basically don't exist, I've even searched for E46 CSL thinking something might come up.

The only ones that do appear are on Ebay and the guy is selling a whole front and rear set for 3K.... they don't have to be OME, just anything that'll fit.
I've already had to return a set as the part numbers were wrong

I want to refurb my rear brakes, but as its my daily I cant be without a car, and rushing a brake job is just asking for trouble.


Back story:
Note: This is my first RWD car.
Under heavy braking my rear left wheel will lock, at first I thought I had downshifted and didn't rev match properly. Tipped into a left hander and then the wheel locked and dragged. Just assumed it was driver error.

Then I went for a drive down the lanes and something felt a little odd, so I hit the brakes in a straight line and it locked again. Then I noticed a squeaking noise. Now i'm thinking its a sticky calliper.

I replace the guide pins (they were corroded) and rubber boots and went for another drive and did the same manoeuvre, and it still locked the rear left. Now its likely a full refurb with the piston out.

Bought a set on Ebay with part numbers that matched, but they were for the normal Z4 so i've had to return them. Although when I had the brakes off I pushed the piston back and forth a few times to try and loosen it up. Squeaking has gone for now, but its only a temporary fix.
Would love a set of AP's, but ££££. One day.

 

[Mr Tidy]

Firstly welcome to the forum.

My Z4M had new front pads, discs and calipers last month which are the same as M3 CSL parts, but my Indy said the rear discs needed replacing soon - maybe when my credit card has recovered!

But he said the rears are standard M3 parts, but this means the discs seem to be hard to get hold of.

It's just a thought but could the handbrake shoes be a factor? My handbrake often sticks and I've read about the lining material coming off.

Hope you can get it sorted, and don't forget we like to see photos of members' cars.

 

[_Paclunch]

Discs are costly, but they do last a while... as long as you don't get pad deposits on them!

After some digging I found that the E46 M3, M3 CP, M3 CSL and the Z4M all use the same rear discs. But the calliper itself is only common between the CP, CSL and the Z4M.

My friend also suggested to check the hand brake. I think I'm just going to have to just refurb the callipers on the drive, so I'll clean the drums then.
After another day of searching the only rear callipers that are coming up are from the US, and they're $500 excluding shipping and tax. For that price your halfway to a BBK.

 

[gr3mlin]

Dropped you a PM

 

[_Paclunch]

Received the PM, but I cant reply.
I get the "We are sorry, but you are not authorised to use this feature. You may have just registered here and may need to participate more in discussions to be able to use this feature."

Anyway, I've just decided to do the piston replacement on the roadside (for now). Service sheet says to depress the clutch all the way down, this will stop brake fluid leaking from the hoses and will prevent air being sucked back into the system.

Fingers crossed all goes well. If not I'll try to message you.

 

[Mr Tidy]

You've made 3 posts now so you can send PMs.

Anyway good luck getting them sorted.

 

[_Paclunch]

TLDR: If you have other options, don't refurbish the brakes on the drive.

New pistons and seals have been fitted to the rear callipers and the car slows down (so the brakes work). I fitted new pads so I'll let them bed in for a bit before I push it to see if the rear still locks.

Below are some photos of the process. It took me about 6 hours (including setup and brake bleed), and a walk to the local garage for them to shoot out one of the pistons with compressed air.
Previous owner had the callipers "refurbished", read that as a paint job... so I had to remove a fair bit of paint and grime from the dust boot sealing edge.

Most of the tools for the job are in the picture but you'll also need a brake bleed kit and the standard torque wrenches and lifting equipment. Air compressor highly advised.

While I'm confident I could do it again on the front, I won't stress myself out and would go with the original plan of getting some replacements first before taking the brakes off.

If you are thinking of doing this job, get some brake lines with Banjo Bolts. Having to rotate a heavy brake calliper in the air without putting tension on, or cross threading the calliper is a nightmare.

 

[Zedebee]

If you are thinking of doing this job, get some brake lines with Banjo Bolts. Having to rotate a heavy brake calliper in the air without putting tension on, or cross threading the calliper is a nightmare.

Too true. When you get to do the fronts, they are much heavier.

 

[swanicyouth]

FYI Z4M & USA e46 M use the same front calipers - brackets are different. I think part #s may have been initially different as paint is different if I recall.

For the rears, the diff between e46M USA & Z4M is the size of the pistons. I don’t recall which is bigger, but it’s not a huge difference. You can swap USA spec e46 M3 calipers into Z4M w/o issue or bracket change. This is useful as Z4 M rear calipers are rare & a small fortune new if available at all. E46 M3 USA spec calipers are available as rebuilds (usually) & are cheaper. Z4 M rear rotors are the same size as e46 M USA rotors & can be swapped w/o changing calipers or brackets - obviously one is drilled & one not, but they can be swapped w/o changing anything else; dimensions are the same.

USA spec e46 M3 has solid iron rotors & Z4M has semi floating drilled rotors, which I believe is the same as Euro spec e46 M3 / CSL / ZCP; but I’m not sure what the UK got for e46 M3. You can swap front hubs & caliper brackets & use solid iron e46 M3 USA spec rotors on Z4M, which I have done. Why is a reason for another thread. The are ~ 30mm smaller w/ no noticeable change in braking, other than being super smooth compared to a well used set of the drilled semi-floating rotors.