Did I stuff up my GS1100G Master cylinder re-kit??

[Colin Green]

Hi all,

Just a quick check to see if you can see anything wrong with this picture.

When I squeeze my lever the fluid immediately starts to squirt up out of the iddy biddy little small overflow hole in the bottom of the reservoir. The lever travels 30% of the way until it stops squirting then starts to apply pressure to the pistons. to get full braking requires the lever to be hard back to the throttle. Have previously re-kitted the MC and just recently re-kitted the calipers and installed braided lines.

The first seal on the end of the spring is positioned just short of the first (larger reservoir hole) and passes that before moving on to also pass the smaller hole.

Did I stuff up the re-kit of the MC

Thanks in advance.

[Colin Green]

I dare say that attaching the picture will help

[Matchless]

Just a question, can you recall whether the metal piston that came out of the M/C was exactly the same length as the new one? They do differ between M/C's.
Usually the lip of the first rubber seal sits just behind the small hole to allow the pressurised brake fluid to release back into the reservoir via the small hole when the handle is released completely. A small movement of the lever should move the first seal past the small hole and thus not push any brakefluid out of it.

[SqDancerLynn1]

Sounds like you still have air in the system

[Colin Green]

Just a question, can you recall whether the metal piston that came out of the M/C was exactly the same length as the new one? They do differ between M/C's.
Usually the lip of the first rubber seal sits just behind the small hole to allow the pressurised brake fluid to release back into the reservoir via the small hole when the handle is released completely. A small movement of the lever should move the first seal past the small hole and thus not push any brakefluid out of it.

Funny you should suggest that, I was wondering if that might be the case as it seemed that it would have made more sense if the rubber returned just far enough. I did the rekit a while back and don't recall checking if the replacement was the same length.

Anyone able to confirm what the length of the 5/8th inch piston (metal bit only) should be??

Sounds like you still have air in the system

I don't believe so... have removed lever and shoved piston in all the way 3 or 4 times, pumped approx 3 litres of fluid through and cracked banjos till I woke up next to my sister... lol

[Nessism]

That plunger looks to be the right one, the round top masters use the longer plunger.

I'm not sure what's wrong with your bike but the bit about squirting fluid sounds normal. I'm guessing the problem lays with air as Lynn says or maybe something binding in one of the calipers, either sliding pins or a piston.

[Colin Green]

That plunger looks to be the right one, the round top masters use the longer plunger.

I'm not sure what's wrong with your bike but the bit about squirting fluid sounds normal. I'm guessing the problem lays with air as Lynn says or maybe something binding in one of the calipers, either sliding pins or a piston.

Cheers Nessism,

Other here have advised that the fluid should squirt up when lever is returning, rather than at the beginning of lever application. Do you disagree (i.e.. believe that the little fluid fountain should start as soon as you touch the lever)?

Thanks for your time

[Nessism]

As I recall, the fountain starts when pulling the lever, not on return.

[Matchless]

Just an afterthought - many M/C's have a small diffuser plate over the small hole and that may be specifically to stop a tower of fluid like you are seeing. If yours is working well and the kit was no different from what was in there I would say ignore it and ride.