Anyone disassembled / rebuilt a EPB rear caliper?

Waderider · Dec 3rd, 2017, 12:41

First up I'm a numpty. Yesterday evening I managed to pop the brake cylinder out of the rear caliper. I did this by the amateur plonker method, pushing the brake pedal while there was no pads or rotor on one side. The brake cylinder pushed past its hydraulic seal but the dust seal retained it, so hopefully no dirt in the system.

So right now I am attempting to get the cylinder back in as a last ditch effort before ordering a new caliper.

Has anyone any knowledge of the internals of the caliper, electronic parking brake, solid rotor? I've pushed the cylinder back in slightly but it'll go no further. The EPB input at the back of the caliper will spin but doesn't help me get the cylinder further back into its housing.

I've been looking on youtube for a strip down or refurb video for one the these calipers with no luck.

Should I just pay the price and order up a new caliper or is there a magic trick for getting this brake cyclinder back in?

Thanks.

ljames28 · Dec 3rd, 2017, 13:46

I've actually had the rear caliper apart to replace a damaged dust boot, if you've got the piston back in a little and dead straight it could be the EPB blocking it. You wind it back in with a 9V/12V power source. If I remember correctly the EPB portion is a threaded rod with a "thing" on the end that mates with the back of the piston. The "thing" fits into a groove in the back of the piston and it has to be rotated the correct way, so maybe try pulling the piston out a bit, applying power to spin it in the hope it orientates correctly, and then putting the piston back.

apersson850 · Dec 4th, 2017, 11:01

You have to screw the parking brake back in first, to give space for the pistone. If it spins freely where the motor normally connects, it hasn't reached the end position yet.

green van man · Dec 4th, 2017, 20:52

I have retracted the piston with a proprietary tool once the ehb is wound back to replace pads.
In your position having pushed the piston out too far it should push back in with the same type of tool.
Piston is sealed to the caliper by a square edged seal, ( possibly a slight taper to the face ) once you have the piston started on passing through that seal it will push in as normal. The trick is in making sure the piston is lined up so you don't pull the seal from the locating groove in the caliper.
I have found when replacing pistons a little rubber grease around the seal is a great help but that is before fitting the dust seal which you still have in place. In your case it will be working by feel until you feel the piston enter the seal then even pressure to push it home squarely.

You have nothing to loose by trying to get it back in and could possibly save yourself a considerable sum of money. Last rear caliper I priced with Volvo was about £100 with the vat, I got a pair from local motor factors for £160. Both Volvo's and the factors were reconditioned parts not new.

Paul.

Semnoz · Dec 6th, 2017, 08:10

There's a cut-away diagram of the caliper, and a bit more info here:

http://forums.swedespeed.com/showthr...job-screwed-up

Dec 3rd, 2017, 12:41	#1
Waderider Slow git Last Online: Apr 11th, 2024 22:09 Join Date: Sep 2009 Location: Gairlochy	Anyone disassembled / rebuilt a EPB rear caliper? First up I'm a numpty. Yesterday evening I managed to pop the brake cylinder out of the rear caliper. I did this by the amateur plonker method, pushing the brake pedal while there was no pads or rotor on one side. The brake cylinder pushed past its hydraulic seal but the dust seal retained it, so hopefully no dirt in the system. So right now I am attempting to get the cylinder back in as a last ditch effort before ordering a new caliper. Has anyone any knowledge of the internals of the caliper, electronic parking brake, solid rotor? I've pushed the cylinder back in slightly but it'll go no further. The EPB input at the back of the caliper will spin but doesn't help me get the cylinder further back into its housing. I've been looking on youtube for a strip down or refurb video for one the these calipers with no luck. Should I just pay the price and order up a new caliper or is there a magic trick for getting this brake cyclinder back in? Thanks.

Dec 6th, 2017, 08:10	#5
Semnoz Senior Member Last Online: Nov 12th, 2023 19:03 Join Date: Jan 2011 Location: NW	There's a cut-away diagram of the caliper, and a bit more info here: http://forums.swedespeed.com/showthr...job-screwed-up __________________ V70 D5 185 SE Lux P3 (with rear integrated booster seats, which the kids love !!)

Dec 3rd, 2017, 13:46	#2
ljames28 New Member Last Online: Jan 22nd, 2024 13:02 Join Date: Dec 2016 Location: Unknown	I've actually had the rear caliper apart to replace a damaged dust boot, if you've got the piston back in a little and dead straight it could be the EPB blocking it. You wind it back in with a 9V/12V power source. If I remember correctly the EPB portion is a threaded rod with a "thing" on the end that mates with the back of the piston. The "thing" fits into a groove in the back of the piston and it has to be rotated the correct way, so maybe try pulling the piston out a bit, applying power to spin it in the hope it orientates correctly, and then putting the piston back.

Dec 4th, 2017, 11:01	#3
apersson850 Premier Member Last Online: Apr 17th, 2024 21:40 Join Date: Jul 2011 Location: Traryd View Photos By: apersson850	You have to screw the parking brake back in first, to give space for the pistone. If it spins freely where the motor normally connects, it hasn't reached the end position yet.

Dec 4th, 2017, 20:52	#4
green van man Premier Member Last Online: Apr 11th, 2024 09:21 Join Date: Nov 2012 Location: Ffos y Ffin	I have retracted the piston with a proprietary tool once the ehb is wound back to replace pads. In your position having pushed the piston out too far it should push back in with the same type of tool. Piston is sealed to the caliper by a square edged seal, ( possibly a slight taper to the face ) once you have the piston started on passing through that seal it will push in as normal. The trick is in making sure the piston is lined up so you don't pull the seal from the locating groove in the caliper. I have found when replacing pistons a little rubber grease around the seal is a great help but that is before fitting the dust seal which you still have in place. In your case it will be working by feel until you feel the piston enter the seal then even pressure to push it home squarely. You have nothing to loose by trying to get it back in and could possibly save yourself a considerable sum of money. Last rear caliper I priced with Volvo was about £100 with the vat, I got a pair from local motor factors for £160. Both Volvo's and the factors were reconditioned parts not new. Paul.

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