stuck brake calipers - tools

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garyinwestoz
Posts: 327
Joined: Thu Jan 29, 2009 9:05 pm
Location: perth, australia
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stuck brake calipers - tools

Post by garyinwestoz »

Last year I wrote about resealing a brake caliper and how I went about that
recently I decided to overhaul a few other calipers I have - so they would be good spare parts.

one of these calipers had a real stuck piston, so in my search on youtube for a solution I came across this system - using a Diesel injector test pump
these are are like $120 online
[youtube][/youtube]

I also found some youtube video of people converting a bottle jack into a Diesel injector pop tester
figure a cheap bottle jack - $30 is something I could do.
a bit like this one.
[youtube][/youtube]

So I dismantled a bottle jack, removed the central piston, and with my Dad, turned up a component that inserted into the jacks top, locked in place by the Jacks lock collar. This component has a center hole with a M10 x 1.0 thread for screwing in a brake hose. I used 3 x O-rings to stop the leaks, didn't include a pressure gauge.

bottle jack piston removed
Image


screen shot of sketchUp model of fabricated component (white) ( just made this model to show the component - as I don't have any photos of the component)

it is 28 mm dia, with 34 mm dia lock ring and 20mm long made from aluminium.

component is white, bottle Jacks screw cap is blue
Image


Image


fabricated insert inserted!
Image

everything connected

Image

So today , I manage to release all 4 pistons from 4 calipers.

I just use a rubber hose and a steel line to connect the jack to the caliper. It takes like 1 min to change calipers - This is so much easier than mounting calipers to the car brake system and using that to push the pistons out.
77 528i -4 speed manual getting rusty
76 525 - 4 speed, LPG and holley carb- restoring
81 528i - auto - to be relicensed with a 3.5 (83 735i)
80 528i auto - ready to relicense
79 SA ? 528i auto
79 528i auto parts car
86 525e 5 speed manual- dd
garyinwestoz
Posts: 327
Joined: Thu Jan 29, 2009 9:05 pm
Location: perth, australia
Contact:

Re: stuck brake calipers - tools

Post by garyinwestoz »

something I should add.

I thought because that these caliper require 2 input lines, that I would need to somehow block off a line as the tool only has 1 line output. So I bought some M10 x 1.0 thread bolts.

but

it seem that the 2 inputs are in fact completely separate - as I ended up not having to block a line for the hydraulic pressure to work with only 1 input line!

I merely swapped over the connection from the top hole to the bottom hole.

I guess in the bigger scheme of things, the ATE/BMW engineers at the time figure they ought to build in a 2 line system, so if one fails - the other one atleast still provides some braking capability or it stems from the early 70's E9 racers!
77 528i -4 speed manual getting rusty
76 525 - 4 speed, LPG and holley carb- restoring
81 528i - auto - to be relicensed with a 3.5 (83 735i)
80 528i auto - ready to relicense
79 SA ? 528i auto
79 528i auto parts car
86 525e 5 speed manual- dd
garyinwestoz
Posts: 327
Joined: Thu Jan 29, 2009 9:05 pm
Location: perth, australia
Contact:

Re: stuck brake calipers - tools

Post by garyinwestoz »

there is also a series of youtube videos , whereby the pistons are rotated and removed via use of a socket .

I tried this as well, but found it too difficult to get a socket and ratchet into the small space we have in our calipers between the opposite pistons

[youtube][/youtube]

[youtube][/youtube]
77 528i -4 speed manual getting rusty
76 525 - 4 speed, LPG and holley carb- restoring
81 528i - auto - to be relicensed with a 3.5 (83 735i)
80 528i auto - ready to relicense
79 SA ? 528i auto
79 528i auto parts car
86 525e 5 speed manual- dd
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