1977 GS750 Rear master cylinder woes

[nickjtc]

The refurbishment of the bike which has come back to me after 33 years away, continues. The bike was parked for 20 years with water caught in the rubber boot at the bottom of the rear master cylinder assembly! Needless to say the circlip has rusted solid and is resisting any efforts to remove it so that the innards can be examined and replaced.

Has anyone successfully drilled out the bottom of the assembly to free up and release the piston/cup? I suspect it will be a fruitless exercise and will just have to source a whole new set-up. Any ideas where to look apart from eBay?

Thanks in advance! Nick

 

[Andy24]

have you tried to heat it with a torch and rotate to release it? i released some cars pistons this way...

 

[tkent02]

Just replace the master cylinder. Ebay is your friend.

 

[Atwood]

If you don't want eBay looks like you can still get what you need new for $170.
http://www.suzukipartshouse.com/oemparts/a/suz/50d3febff8700230d8b4dc97/rear-master-cylinder-gs750c

 

[nickjtc]

If you don't want eBay looks like you can still get what you need new for $170.
http://www.suzukipartshouse.com/oemparts/a/suz/50d3febff8700230d8b4dc97/rear-master-cylinder-gs750c

Thanks for that. Although I have no qualms about changing the bike from 'stock' (I have already put Euro bars on it to replace the N. American high ones) I am reluctant to get into anything that will require fabrication. That assembly has the remote reservoir which would entail fabricating a bracket to mount it. The stock master cylinder/reservoir set-up is all in one piece with the reservoir perched on top.

 

[nickjtc]

Ebay is your friend

Yes, there are several on eBay now. However the sellers are not responding to the question as to whether the circlips are 'free', and I am reluctant to get another unit and find myself in the same situation as I am with the one I've got.

 

[nickjtc]

tried to heat it

Didn't think of that as an option, but there is nothing to lose, even though the circlip is a rusted mess. Thanks

 

[chuck hahn]

Circlips have broke on me before due to rusted thru. But usually you can just throw the entire thing in a vat of vinegar for a few days. The rust gets eaten but the rubber cups inside and such stay unaffected. Take the boot off and set it in a coffee can or something..use the 8% vinegar.