1979 gs850g Front brake master cylinder (square) leaking, suggestions to replace ?

[seanarthurmachado]

Hi everyone,


My front brake master cylinder appears to have developed a small leak.
I went out to the shed to start the old bike up and Ive been noticing that the header pipe from cylinder #4 (right hand side) is smoking. I originally thought it might be needing a gasket but on closer inspection its burning an oily substance that was hitting the pipe.

On examination I found the reason I needed to top off my front brake cylinder...a small leak from the under-side of the square cylinder box.

Not coming from the banjo bolt. Who knows perhaps I damaged it when removing a stuck bolt on the top cover of the master cylinder a couple months ago.

The bike has the square type with a window, appears to be metal. (Maybe off a gs1000 ?)

Ive been told that the master cylinder for the front brakes on a 1979 should have been a round model.

Now on to my question:

should I buy a new "container" from ebay and try to rebuild or just replace the whole unit ?


Sean

[Guest]

Pretty easy to find a good used set on here if you post an ad. You'll need more than just the one part if you're going to rebuil it.

[seanarthurmachado]

so used OEM and just replace ?

sean

[fastbysuzuki]

Yes it's listed as a round one but if the brake works ok why change it? If it's leaking from under the oblong plastic reservoir
you will have disturbed the oring that sits under the reservoir, you can get this part, you will have to drain the system the reservoir just pulls of the mounting quite tight it's only held by the four screws that fasten the top of the reservoir.
cover paint all when removing the reservoir.
does yours look like this it's off a gs 850 gl d 1983 https://www.z1enterprises.com/product/KL32-8059
the link below is for a site in the uk but it does give you the Suzuki part number, I have just fitted one on my gs850gx uk

https://www.discountbikespares.co.uk/ourshop/prod_968344-O-RING-MASTER-CYL-RESERVOIR-GT250-X7-GT200-X5-GS1000-GS850.html

[seanarthurmachado]

My front brake master cylinder looks similar but no plastic. It's the same shape but all metal with a small circular window in the front. The top screws are small and only hold the cover to the top but do not go down to hold onto anything but the cover

[seanarthurmachado]

CameraZOOM-20151205164229389~2.jpghere is a picture

[fastbysuzuki]

I have to admit I have never seen a metal reservoir on a front brake so I cannot help any more sorry, perhaps someone else can throw some light on the problem, or it may be better to revert to original spec.

[Grimly]

Or you could fit one from an NTV650 / 700 / Deauville (15mm / 5/8th bore same as yours) and get the benefits of a click-stop adjustable lever and a much nicer feel.

[seanarthurmachado]

I ended up buying one of these from ebay and am waiting on delivery:

http://www.ebay.com/itm/271183218282?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Its a 16mm/ 5/8" assembly.

(on a casual ebay search I found a couple used brake assemblies - like mine from what appears to be 1982. since they want $60.00 for old used and this new one is $30 I think Ill go with new.)

sean

[Grimly]

I ended up buying one of these from ebay and am waiting on delivery:

http://www.ebay.com/itm/271183218282?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Its a 16mm/ 5/8" assembly.

(on a casual ebay search I found a couple used brake assemblies - like mine from what appears to be 1982. since they want $60.00 for old used and this new one is $30 I think Ill go with new.)

sean

It's your neck. Crappy cheap Chinese brake parts don't get near mine. I'll cheap out on a lot of things, but rubbishy brakes don't figure high on my must-have list.
An NTV m/c would cost about the same, and it's decent quality to start with; even if it needs a rebuild at least you can be sure of what you have.