R1100GS Front brake master cylinder assembly

[Brodie13]

Hi all,
Has anyone got a complete, working assembly to replace mine that’s certainly seen better days?! I’m not too sure that I’ll be able to remove the cap due to the couple of buggered screw heads. So may not be worth ordering a repair kit in the hope that it can be salvaged? Opinions from folk who have faced the same issues would be much appreciated. Thanks

 

[Paul Young]

Hi all,
Has anyone got a complete, working assembly to replace mine that’s certainly seen better days?! I’m not too sure that I’ll be able to remove the cap due to the couple of buggered screw heads. So may not be worth ordering a repair kit in the hope that it can be salvaged? Opinions from folk who have faced the same issues would be much appreciated. Thanks

Motorworks is probably your best bet…

 

[chopper_harris]

Checking the parts fiche, the front m/cyl unit for the R1100GS is common to all the R and K bikes from 1989 to 2001 ish.

You may find a decent pre-loved part from a reputable seller - eBay Germany is likely to have a better selection.

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Quote Reply

 

[DrFarkoff]

A scoot of ACF50 a day or so before just dripped on / in around the screws

Then Boiling water first and then a tap with an Impact driver and "Robert would be your fathers Brother"

The ACF has already started to steep in and the hot water poured gently and slowly on swells the alloy more than the steel

and the impact driver completes the picture Just break each one loose until you can get it moving with a screwdriver and move to the next one to reduce possibility of brake fluid splashing when you are thumping the impact driver

I advise either removing or protecting the tank from possible Brake fluid spatter

If they are that bad "mig"-ing an M6 bolt or a bit or a screwdriver to the screw can generate enough heat and get you enough leverage to get them out If the above does not work

Oh and P.S. the Boiling / very hot water also has the benefit of dissolving the brake fluid crystals that usually infect this job !

 

[Wrigsby1]

Hi all,
Has anyone got a complete, working assembly to replace mine that’s certainly seen better days?! I’m not too sure that I’ll be able to remove the cap due to the couple of buggered screw heads. So may not be worth ordering a repair kit in the hope that it can be salvaged? Opinions from folk who have faced the same issues would be much appreciated. Thanks

Yep, as said, I have rescued things like this but it's mainly whether it's leaking or overly corroded in the piston area... A wee Dremel slot on the screwheads can give you more purchase too...
Problem is they are hidden behind the handguards and you get a shock if they haven't been off for a long while...

 

[Steptoe]

Couple of drops of EZ Grip, they do “aircraft” grade or.”Marine” grade. I have aircraft grade, due to my friend and neighbour being an aircraft engineer

And a proper screwdriver bit made for extracting knackered screws, Snap-on make one.

 

[Brodie13]

Thanks chaps for your very welcome advice! Front brakes were working fine until I pushed back the pistons when servicing the calipers and that must have been the last straw for the master cylinder assembly……Ill give it a go over Christmas!

 

[Riceburner]

Make sure you use the correct screwdriver head for the screws. I can't remember exactly what they are, but for example don't use Pz screwdriver in Ph screws.

 

[DrFarkoff]

Thanks chaps for your very welcome advice! Front brakes were working fine until I pushed back the pistons when servicing the calipers and that must have been the last straw for the master cylinder assembly……Ill give it a go over Christmas!

Also check your front hoses if they're still the Original rubber ones

They delaminate and become one way valves

 

[Brodie13]

Gents….I am VERY happy to report that your helpful tips in mind, I have removed all four screws from the master cyclinder reservoir and to my surprise all looked clean inside and with a top up of fluid my front brakes are remarkably working again without any problems! Thanks again for the advice everyone

 

[Brodie13]

Ordered yesterday from Motorworks….arrived today

 

[Brodie13]

…..these!

 

[DrFarkoff]

…..these!

@Brodie13 Do NOT use coppaslip or the like with those

You need to use an alloy antiseize paste

The copper stainless and aluminium cause a 3 way galvanic reaction when water/salt get into the equation

 

[Brodie13]

Cheers Doc! Happy Christmas