brake fluid fountain

[Redman]

This normal, or indicate a problem?

Am checking into the front brakes on the 82 1100GK. Front master cyclinder is the rectangular one (not round).

When pull on the brake lever, for about the entire first half of the stroke it doesnt really build up any pressure resistance, and if look into the master cyclinder resivour, can see the fluid is squirting up and creating a current in the resivour. If squuezze lever real hard fast thru that first half of the lever travel can almost make a little brake fluid fountain. I can understand that maybe that is okay for maybe the first 10% of the lever stroke untill some seal gets past the vent, but it does this for half way to the bar. This sound familiar to anybody? This a symptom of any particular probelm? I have other things to deal with yet before I get to the master cyclinder, but anybody know what this problem is?

Maybe related: Then the last 50% of the lever stroke, dont see that flow/fountain, and builds up pressure/resistance, but is a bit spongy, goes perrty much within half inch of the bar. SO have been bleeding the lines with not much improvement. Am not asking about the spongy part or the bleeding part, but just stating that perchance its related to the previous stated situation.

[arveejay]

Sounds like either leakage past the cup seal or a plugged hole in the reservoir. There's 2 holes, very tiny, must be open to pull fluid in on backstroke and it may be plugged. Almost sounds like still may be air in MC and a block would explain that.

[fgh]

This normal, or indicate a problem?

Am checking into the front brakes on the 82 1100GK. Front master cyclinder is the rectangular one (not round).

When pull on the brake lever, for about the entire first half of the stroke it doesnt really build up any pressure resistance, and if look into the master cyclinder resivour, can see the fluid is squirting up and creating a current in the resivour. If squuezze lever real hard fast thru that first half of the lever travel can almost make a little brake fluid fountain. I can understand that maybe that is okay for maybe the first 10% of the lever stroke untill some seal gets past the vent, but it does this for half way to the bar. This sound familiar to anybody? This a symptom of any particular probelm? I have other things to deal with yet before I get to the master cyclinder, but anybody know what this problem is?

Maybe related: Then the last 50% of the lever stroke, dont see that flow/fountain, and builds up pressure/resistance, but is a bit spongy, goes perrty much within half inch of the bar. SO have been bleeding the lines with not much improvement. Am not asking about the spongy part or the bleeding part, but just stating that perchance its related to the previous stated situation.

The quick answer is that if the resistance increases as you repeatedly pump the brake you have a bad master cylinder. If the resistance doesn't change as you pump the brake you have air in the lines.

[AOD]

I think the fountain is normal...I'm trying to get my brakes bled on my 1100 and I notice that if I rapidly pull the lever...it shoots a stream straight up!

I swear it did that last year too when I bled the brakes.

~Adam

[denydog]

I think the fountain is normal...
~Adam

I agree, but I think it happens more on the release stroke. Not completely sure. When bleeding my brakes, I always try to remember to squeeze and release the lever in a slow deliberate manner, or else I end up with brake fluid all over the place.

[Nessism]

Fountain is normal.

Don't forget to clean up any spilled brake fluid since it eats paint. Nasty stuff. Stinks too...