1100 front master cyl leaking

[wilcoy02]

This 1100 has had brakes replaced and cleaned.
Could not get any braking from the front. Got it bled ok, but no stopping power.

I tied the front brake lever to allow any bubble to rise to the top. Noticed when I came back to the bike in an hour or so, brake fluid was slooowwly dropping off the bottom of the lowest point.
I can not see any leaking from the bottom of the reservoir or above.

What am I missing?

 

[Gc33]

wilcoy02 » Today- 20:11[/url]":35oosa45]
This 1100 has had brakes replaced and cleaned.
Could not get any braking from the front. Got it bled ok, but no stopping power.

I tied the front brake lever to allow any bubble to rise to the top. Noticed when I came back to the bike in an hour or so, brake fluid was slooowwly dropping off the bottom of the lowest point.
I can not see any leaking from the bottom of the reservoir or above.

What am I missing?

Check the Junction where the 2 front brake lines come out. Make sure all are tight and more importantly all have the correct copper washers on them too. Can leak from those spots... Where brake lines connect up...
Or you have a pin hole in one of your lines?
Really it's a process of elimination... Like most things on these ol girls...

 

[wilcoy02]

The leak is above the handle bar. I thought it was the seal at the bottom of the reservoir. I see no leak there. It leaks when I have the brake lever tied.

 

[Gc33]

I've been giving this some thought.... Maybe a fine crack on the cylinder body? Only 2 places it can leak... From the Oring or where hose connects. If wrong washers used it won't seal... If over tightened it could crack the housing or strip the threads is more likely... Failing that I'd have a look and put a new front master on. Not real expensive... $45US at David silver spares
Only other place is the lid and reservoir diaphragm... They don't last forever... But if as you say it's only when you have the brake lever in... I'd be checking connection point.. Washers and thread... Or crack in housing.

 

[saganaga]

Was the master cylinder rebuilt as well?

 

[Gc33]

saganaga » Yesterday- 19:37[/url]":qjz1vtf8]
Was the master cylinder rebuilt as well?

If they have rebuilt the master but only put new piston etc in they aren't worth a pinch of the proverbial poo.
That's why I opted to have both mine stainless sleeved. Lifetime guarantee...
Not much can go wrong with the master front tho.. If it leaks its either the lid/diaphragm, the reservoir Oring U/S or the connections are loose or dodgy.
Seeing he said it's only when lever is pulled on... It's gotta be the line/hose connection or a minute crack that let's out fluid only when under pressure?

 

[Dusterdude]

Gc,who did your sleeving?

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[Gc33]

Dusterdude » Today- 14:33[/url]":3eh1wh9z]
Gc,who did your sleeving?

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Place here in Perth. Perth brake and clutch
https://www.perthbrakeparts.com.au/?utm ... ontent=gmb
Weren't cheap but considering my options...

 

[Dusterdude]

Groovy,thanks

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[Gc33]

Dusterdude » Today- 20:43[/url]":2ahlmh4o]
Groovy,thanks

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I'm sure some brake place near you would do this... But considering our exchange rate you'd have it shipped fixed and returned a a good price..

 

[Dusterdude]

I hear ya

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[chilidawg]

wilcoy02:

I assume this is your 81 that's having this issue, if so, then are you sure you are using the 14mm front master cylinder rebuild kit.

I once had this problem when I didn't know the difference between the standard (up to 82) system and linked 83 brake systems.

A 12mm 83 rebuild kit will give purchase to your 81 dual front brake when fully bled, but it will come all the way back to the handlebar to do so.

Could this be your issue?

 

[gwhsr68]

Wipe everything down then sprinkle with a light coat of baby powder. The leak will show itself. Hope this helps.

Gary H.

 

[pidjones]

If you didn't lube everything all up for assembly with brake fluid, the piston rod can pull out of the back cup on the first several pumps. You'll have to put it back through (over the hump on the rod) and lube it well.

 

[wilcoy02]

I had to put the bike on the back burner. Decided to put a metal roof on my garage, when it is 90+ degree out.
Since I can not get the front brake to work . I am planning on putting new line on the front.

 

[Gc33]

wilcoy02 » 2020-07-22- 19:11[/url]":2fm4r1sz]
I had to put the bike on the back burner. Decided to put a metal roof on my garage, when it is 90+ degree out.
Since I can not get the front brake to work . I am planning on putting new line on the front.

New line or new master cyl?

 

[wilcoy02]

Plan to put braided line on.