front brake caliper pistons R1150GS...

maku · Mar 18, 2023

I'm trying to free up dragging pads on the front discs but theres something weird going on with the pistons in the Brembo calipers...are some of them the wrong round?

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DrFarkoff · Mar 18, 2023

They're just anti squeal dampers

Plastic plugs inside the alloy pistons

DrFarkoff · Mar 18, 2023

P.S, its a Pre 2002 R850 1100 / R1150 isn't it??

You need to check the rubber hoses

That may be the issue where the hose liner separates and becomes a one way valve and holds pressure in the lines after you apply the brakes and it takes ages for it to release

Also the Master cylinder is the brake lever loose for the first 10mm of travel ??

Sticky piston Often to blame not returning to the rest position and releasing pressure Likely to drip a little too

Neil W · Mar 20, 2023

When I bought my 1150 last year the lever felt great ie hard with little movement but provided minimum braking force but they were still binding .

Although not corroded every piston in the front calipers was siezed or semi siezed and were absolute b#ggers to remove, the caliper bodies ,however, were immaculate.

I bit the bullet and replaced all of the seals and pistons and fitted Goodridge braided lines and the brakes now are as good as they are going to get for an old bike

Paul Young · Mar 20, 2023

I noticed that my front calipers were binding, so got a friend who loves sorting them for folk to take a look at them for me.

When they came back, he told me how tricky they were needing lots of heat to release one of the pistons. He completely dismantled them and cleaned them up so that the pistons just slide around with finger pressure. I have to admit that they are now really good brakes (again).

maku · Mar 21, 2023

ok thnx for that...so those plastic plugs are just optional?

...hopefully I can just free up the pistons without having to do the seals...Clymer says to blow 'em out with air hose

I think...the bike has braided lines so maybe the one-way valve thing wont have happened?...its a '02 R1150GS with 90k miles...history is unknown

Neil W · Mar 21, 2023

At that age and miles if you have no evidence of a caliper rebuild I would split the calipers , strip them and rebuild with new seals at the very least

maku · Mar 22, 2023

seems like Haynes, Clymer & Motorworks say don't split the calipers...is there some leak risk after assembly?

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Neil W · Mar 22, 2023

maku said:
seems like Haynes, Clymer & Motorworks say don't split the calipers...is there some leak risk after assembly?

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Over the years I have split numerous motorcycle calipers to rebuild including two sets of r1150gs Brembo's ,always replaced the centre seal and never had any leakage issues

theoneandonly · Mar 22, 2023

maku said:
seems like Haynes, Clymer & Motorworks say don't split the calipers...is there some leak risk after assembly?

not if you are careful .

oblertone · Mar 22, 2023

In between the mating faces of the callipers are two very small 'O' rings; they are VERY easy to lose if you do split :blast

Riceburner · Mar 22, 2023

oblertone said:
In between the mating faces of the callipers are two very small 'O' rings; they are VERY easy to lose if you do split

They're also sometimes difficult to find replacements for.

I know that for the Tokico equipped bikes, BMW and Motorworks don't (or didn't) sell those little seals. I'd had Tokicos on Kawasakis before my Rocksters, so I knew thay Kawasaki supplied them and I bought them from Cradley Kawasaki (the suppliers I'd used before).

But I believe the situation with Brembos is better, and they are available more easily, but often only as part of a complete caliper overhaul kit.

maku · Mar 30, 2023

thnx for all tips

...I just freed up the pistons a bit so they're not binding so much now...hopefully do the seals etc in the summer sometime

Hookster · Apr 10, 2023

Just on with this now on my R1150R - set off to the MOT centre and got 2 miles. Thought engine was seizing due to lack of use but no, front brakes jammed on. Freed pads off at road side and rode home using back brakes only. Initially I took Motorworks advice and only go the basic kit but that is still 78 quid a side. Only to find that the pistons needed 120PSI to get them out andante I'd gone that far I thought 'sod it' and split the callipers. I thought it would be O rings to seal the halves but its a proper seal. These on order BUT the seats for the seals have oxidised badly and I'm not hopeful I'll get a good seal when rebuilt. I've got a one-way valve for bleeding when I get that far but any bleeding tips gratefully received as I think I've heard these are a devil to do?

I came here looking to see wha the inserts in the piston are as the originals (2004 Tokico) don't have them!

Good luck with yours when you get around to the refurb!

front brake caliper pistons R1150GS...

maku

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DrFarkoff

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Neil W

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Paul Young

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maku

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theoneandonly

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