I need to change the rear pads on my 96 discovery - and the pistons as they are a tadge rusty. Can i change the pistons without removing the caliper (will they clear the disk)??. if i need to remove the caliper what size & type of socket do i need to fit to the 'star' bolt that holds them in place??. Reluctant to remove the caliper as with my luck the brake pipe will be siezed in, and the job just gets bigger and bigger. Thanks.
brake caliper overhaul
- Thread starter justjon
- Start date
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robint
Well-Known Member
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if i can remember rightly a 13mm ring spanner will fit !!
and yes your have to remove the calipers and brake lines , because your have to replace the seals if your doing the pistons
and yes your have to remove the calipers and brake lines , because your have to replace the seals if your doing the pistons
G-man
BBQ king
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a 13mm ring may fit but you would be better off getting the correct tool for the job! if its a torx you might end up rounding it off then you will be buggered!
discool
Well-Known Member
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I believe it's a 12 point socket/ring spanner required but I have never had to remove a caliper, but I have renewed pistons and seals without removing the caliper back in my RR days..
terryds
Member
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You only need to displace the pistons outwards a little to clean them as they should be clean internally. Therefore put a spacer in before depressing the pedal.
If you find the pistons are rusted, then you will need to remove the calliper as the seals will also likely need replacement.
Make sure you use brake cleaner when carrying out this maintenance.
If you find the pistons are rusted, then you will need to remove the calliper as the seals will also likely need replacement.
Make sure you use brake cleaner when carrying out this maintenance.
rojbarker
New Member
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A standard hex socket will not fit - you need a 13mm ring spanner or 13mm socket that has a star-like internal shape and not a flat hex shape.
Like this one:
Like this one:
EeEk
Well-Known Member
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Is it not 1/2" AF? It is on mine anyway. A normal 12 point socket or double hex as we know them as. 13mm is slightly larger but they are bloody tight so youd be better with the 1/2" as it will have slightly more grip.
No the pistons wont come out with the calipier attached. Before you start check the bleed nipple turns as theres no point in going any further if you cant bleed them or at least be prepared to fix it at the same time. The brake pipe probably wont move and may well need replaced. It would be much easier to replace the pipe and do the job in a vise than try to clean and fit pistons holding the calipier in your hand.
remove the pads..pump the brakes until the pistons touch the disc..remove the calipier...you should then be able to wiggle the pistons out.
Now me...having done many brakes on many cars for many years would split the calipier by undoing the (2x on the rear, 4x on the front) 5/8" (16mm) bolts, depending where you look theres those who say dont split it but it makes it ten times easier to clean the grooves where the seals go....lecky drill and wire brush..
dont half do it. youll only end up doing it again!! fit pistons and seals.
No the pistons wont come out with the calipier attached. Before you start check the bleed nipple turns as theres no point in going any further if you cant bleed them or at least be prepared to fix it at the same time. The brake pipe probably wont move and may well need replaced. It would be much easier to replace the pipe and do the job in a vise than try to clean and fit pistons holding the calipier in your hand.
remove the pads..pump the brakes until the pistons touch the disc..remove the calipier...you should then be able to wiggle the pistons out.
Now me...having done many brakes on many cars for many years would split the calipier by undoing the (2x on the rear, 4x on the front) 5/8" (16mm) bolts, depending where you look theres those who say dont split it but it makes it ten times easier to clean the grooves where the seals go....lecky drill and wire brush..
dont half do it. youll only end up doing it again!! fit pistons and seals.
Mr Noisy
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I'd recommend against splitting the caliper - sole reason that you may make leaks and you probably don't need to split just the clean the cylinders.
However, you may not make leaks and you might need to split to clean properly, so you decide.
For the brake pipe, get a piece of heavy bar and hammer down on the brake pipe union, as if to hammer it into the caliper. Do this all around it, hard enough to hurt it but not to damage the union. This action will help to loosen the rust etc that will hold it in.
Then you need a 7/16" or 11mm flare nut spanner, which is a heavy duty ring spanner with a slot cut out of the end. Tap it round to loosen the nut (which probably will come undone) and then wiggle to free it from the brake pipe - this may take a few minutes of careful wiggle n lube...
I find it is easier/more successful to use a good socket on the bleed nipple on the bench rather than a spanner on the car, but a spanner may do, depending on rust.
It might be worth getting new bleed nipples from britpart seeing as you're overhauling, they're cheap and nice and new again.
Regards the pistons, I just cleaned up my fronts on my 91 and they were quite rusted, but I didn't fancy 40 quid just on pistons at the moment, so I went for new seals alone. Superb braking and no dragging, new pistons may be needed in a year or so, maybe not...
Anyway, that's all I have to say,
hope it helps
However, you may not make leaks and you might need to split to clean properly, so you decide.
For the brake pipe, get a piece of heavy bar and hammer down on the brake pipe union, as if to hammer it into the caliper. Do this all around it, hard enough to hurt it but not to damage the union. This action will help to loosen the rust etc that will hold it in.
Then you need a 7/16" or 11mm flare nut spanner, which is a heavy duty ring spanner with a slot cut out of the end. Tap it round to loosen the nut (which probably will come undone) and then wiggle to free it from the brake pipe - this may take a few minutes of careful wiggle n lube...
I find it is easier/more successful to use a good socket on the bleed nipple on the bench rather than a spanner on the car, but a spanner may do, depending on rust.
It might be worth getting new bleed nipples from britpart seeing as you're overhauling, they're cheap and nice and new again.
Regards the pistons, I just cleaned up my fronts on my 91 and they were quite rusted, but I didn't fancy 40 quid just on pistons at the moment, so I went for new seals alone. Superb braking and no dragging, new pistons may be needed in a year or so, maybe not...
Anyway, that's all I have to say,
hope it helps
