BMW E46 Brake Calliper Reconditioning

friendface

Hey, I posted on here lastnight looking for advice on replacing rear brake pads & discs. After, removing the pads, I noticed the calliper piston appears to be extremely rusted.

As I mentioned yesterday, this is my first brake job so maybe this is normal. The brakes had been sticking slightly in the past which may account for the increased pad wear.

Anyway, I've attached a few images of the piston from the Rear Left Side. I've no experience reconditioning pistons. Would this be a difficult job. Should I just leave it as is as it seems to be working alright.

Thanks again for all the help!



Larger



Larger

Additional details: 2001 BMW E46 320D SE (imported from Belfast)

dharn

thats in a desperate state and should be replaced immediately the other side also as you need two calipers working equally well or your car will not be safe in emergency braking esp on wet road never take shortcuts with your brakes

listermint

Christ, they are poor. Must be the salt i presume. Whats the service history like on the car? Doubt those babies have seen an ounce of Copper Grease.

Id be inclined to check all x4 disks on that car.

friendface

listermint wrote: »

Christ, they are poor. Must be the salt i presume. Whats the service history like on the car? Doubt those babies have seen an ounce of Copper Grease.

Id be inclined to check all x4 disks on that car.

Car had Full BMW Service History from new. I had the front brakes done recently by an independent mechanic and he didn't mention anything about the calipers being in a poor state. Would it be possible to recondition these myself or do they really just need to be replaced?

listermint

friendface wrote: »

Car had Full BMW Service History from new. I had the front brakes done recently by an independent mechanic and he didn't mention anything about the calipers being in a poor state. Would it be possible to recondition these myself or do they really just need to be replaced?

Being Honest, id want new ones. But Id give it a go cleaning the face and visible sides down with a steel brush and get the initial dirt crud and rust off them. make a judgement then. This type of rust shouldnt be happening with a FBMWSH.

friendface

listermint wrote: »

Being Honest, id want new ones. But Id give it a go cleaning the face and visible sides down with a steel brush and get the initial dirt crud and rust off them. make a judgement then. This type of rust shouldnt be happening with a FBMWSH.

Ok, I decided to call a couple of breakers yards to get a quote on replacements. The yard I called in Galway want €200 for a pair taken off a '01 E46. I then called Traynors in Armagh who offered a pair for £30 each. I've put in a provisional order for these as they only have 60k miles on them. In any case they are bound to be better than what I have.

I'm also waiting on a quote from BMW out of interest.

What started out as a simple brake job got a hell of a lot more complicated and costly I guess it's good experience but not I wanted for my first job. Any good guides on replacing callipers and bleeding brakes feel free to send them on. Thanks guys

friendface

Does anyone know if I necessarily need to bleed all the brakes after changing the two rear callipers or can I just top up the master cylinder and pump some of the old fluid through the bleed screw on each new calliper? I checked the service history and the brake fluid was last done at 86k miles (Aug '07) at the same time as the rear pads. There's currently 118k miles on the car.

Nissan doctor

friendface wrote: »

Does anyone know if I necessarily need to bleed all the brakes after changing the two rear callipers or can I just top up the master cylinder and pump some of the old fluid through the bleed screw on each new calliper? I checked the service history and the brake fluid was last done at 86k miles (Aug '07) at the same time as the rear pads. There's currently 118k miles on the car.

Those do look pretty bad but its the seals that you really need to check. Clean off as much of the rust/dirt as you can and then inspect the seals for tears etc. If the seals are damaged then corrosion can get in between the piston and the cylinder and cause the piston to stick.

The brake fluid should be changed every 2 years regardless of the miles covered and you'd need to bleed the whole system after changing the calipers as the master cylinder will drain unless you clamp the brake pipes(don't use a visegrip).

The subject of main dealer servicing has come up a couple of times already, it doesn't surprise me that the calipers would be in that state with a full history as the German manufacturers only measure the pad thickness through the wheels during a service, so basically don't properly inspect the whole system. Unless the pads were replaced then BMW would never see the caliper in that condition.

As for replacements, if you didn't want to chance second hand ones(ones coming from the north/uk could well be in the same state due to salted roads etc)Try any decent motor factors for a price. You'll get new ones for a fraction of the price of BMW.

friendface

Nissan doctor wrote: »

The subject of main dealer servicing has come up a couple of times already, it doesn't surprise me that the calipers would be in that state with a full history as the German manufacturers only measure the pad thickness through the wheels during a service, so basically don't properly inspect the whole system. Unless the pads were replaced then BMW would never see the caliper in that condition.

I just rechecked the service history. According to the Maintenance manual, the car was serviced at 86253miles on 23/8/07. On this date a Grade II inspection was carried out as well as a replacement of Rear Brake Pads. I find it hard to believe that the calipers have deteriorated to their current state since I imported the car in July 2008.

I have a breakdown of whats included in a Grade II inspection. It includes:

Disc brake pads front and (if fitted) rear: remove and install, check overall thickness. Clean out calliper cavities, renew pads if necessary.
Brake Discs: check surface condition and thickness, including parking brakes.
Alloy wheels: grease centering spigots.

However, looking at the calipers, it appears they've spent the last 10 years at the bottom of the sea

I think I'll get the replacements from Traynors if they are in good condition, unless I find a reasonably priced new replacement. I wouldn't like to leave the existing callipers on the car. Looks like they're too far gone. As I said, I believe the left rear calliper had already started seizing.

Thanks again for all the replies.

Nissan doctor

Probable shows how little having a main dealer service history means sometimes.

If I were you I'd have a good look at the steel brake lines under the car to check for rust too if the calipers are that bad.

Arthur Daley

Nissan doctor wrote: »

If I were you I'd have a good look at the steel brake lines under the car to check for rust too if the calipers are that bad.

Yes, these rot like an apple on the e46, and it's a tank down job.

friendface

Thanks, I'll check those over the weekend, must see if I can get a loan of some car ramps The brake lines running into the calipers seem okay but I guess these connect into another steel brake line system under the car? I'll have a good look underneath when I get the chance anyway.

dharn

to op im glad you are replacing them as was my advice ,im amazed how rotten those were as you said its like the were in the bottom of the sea for 10 years service history does not inspire much confidence looking at those i would be keeping a close eye on the wheelarch edges etc i have seen an imported 3 series recently and the paint is starting to blister at the edges of the wings where the wheel arch liner meets it

dharn

btw you sometimes find bmw parts can be cheaper than motorfactor spurious parts, but if it is a part that cannot be gotten in a motor factors ie no competition, they will rob you, i got coil packs cheaper in bmw than motorfactor could supply