Front brake locked up

[gssuzukixxx]

'79 GS850

During my ride today I noticed the bike labouring...thought it was the engine siezing up. But when I stopped I notice the bike did not roll freely. Turns out the front brakes are dragging to the point that the bike will hardly move. Both front discs are very hot and discoloured to I assume it is in the master cylinder.

Right now it is sitting at a strip mall...any ideas how to release the brake so I can at least get it home? Also what would be the cause/cure for this?

Thanks
Brian

 

[SqDancerLynn1]

Chances are the brake fluid is not returning to the master cyl because it is gummed up You need to take the master cyl off and clean it- flush it with brake fluid, clean the tiny holes in the bottom of the fluid resivoir to get it working. If you plan on keeping the bike I would get a rebuild kit

 

[Nessism]

Maintenance is good. Said another way, lack of maintenance is bad and may get you killed.

Time to clean out the brake system and replace those 30 year old rubber brake lines (unless you have already done so).

 

[gssuzukixxx]

Thanks guys,

I went back to the bike and everything was cooled off and the bike rolled freely again. So I rode it home easily using only the back brake.

I hear you loud and clear about the brake maintenance. Have not done any since I bought the bike...intended to but will now. Fluid is brown and milky looking.

Thanks
Brian

 

[TheCafeKid]

If you're going to rebuild it, and start with fresh new stainless lines, I would suggest cleaning it VERY VERY well, and using DOT5 fluid from now on. Its not corrosive, and doesnt pick up water as freely as DOT3 and 4. BUT you HAVE TO CLEAN ALL OF IT! Master, calipers, new lines, all need rebuilt to swap over...

 

[Nessism]

If you're going to rebuild it, and start with fresh new stainless lines, I would suggest cleaning it VERY VERY well, and using DOT5 fluid from now on. Its not corrosive, and doesnt pick up water as freely as DOT3 and 4. BUT you HAVE TO CLEAN ALL OF IT! Master, calipers, new lines, all need rebuilt to swap over...

Cafe (Josh) is an overall good guy but he's wrong on the call for DOT5. Regular DOT 3/4 is preferred since a) it provides a more firm feeling brake lever, 2) it's compatible with commonly available brake fluid should anything happen on the road, 3) it's cheaper.

 

[Steve]

Cafe (Josh) is an overall good guy but he's wrong on the call for DOT5. Regular DOT 3/4 is preferred since a) it provides a more firm feeling brake lever, 2) it's compatible with commonly available brake fluid should anything happen on the road, 3) it's cheaper.

and 4) because DOT 5 fluid does not absorb water, any water that does get into the system will tend to pool in the lowest point and cause corrosion there.

It still requires regular fluid flushes, but for different reasons than DOT 3/4.

One of the main differences between DOT 3 and DOT 4 is the boiling point. For normal street use, DOT 3 will suffice. If you will be road racing and using the brakes a lot on a regular basis, DOT 4 will be preferred. If, for some reason, those numbers are not high enough for you, there is always the option of DOT 5.1. NOT the same stuff as DOT 5, it is still a glycol-based product and is somewhat compatible with 3 and 4.

.

 

[Turtleface]

+1 on the stainless lines. I built mine using Earl's fittings and hose. Easy as pie to fabricate. Lever feel is MUCH improved. Haven't even been able to try it in motion yet, and I can already tell the front and rear are improved. Can't wait to see how much of a difference rebuilding the calipers and master cylinders make, along with new pads. Technology sure has come a long way in the lines and pads department, since 1982.

 

[oldgsfan]

I had exactly this same problem when I first bought my 1980 850 a couple of years back.

I followed everyone's advice here and rebuilt my front brake calipers with new pistons, new seals, rebuilt the master cylinder, put in the stainless steel lines, and so forth.

The one thing I wish I had done was buy a good tool to remove the circlip for the master cylinder. That little bugger gave me more trouble than anything else in the rebuild.

Oh, yeah, and the bleeder kit I had was kind of cheap. I wish I'd had a better one for the job or a friend willing to work the brake handle while I bled the brakes.

Otherwise, it's not hard, just takes a little time.

And I've not had a problem with the brakes since then.

 

[Turtleface]

The one thing I wish I had done was buy a good tool to remove the circlip for the master cylinder. That little bugger gave me more trouble than anything else in the rebuild.

Oh, yeah, and the bleeder kit I had was kind of cheap. I wish I'd had a better one for the job or a friend willing to work the brake handle while I bled the brakes.

Otherwise, it's not hard, just takes a little time.

And I've not had a problem with the brakes since then.

I picked up a set of Channel Lock circlip pliers at Home Depot to change my oil pump gears. The tips are interchangeable(different sizes, straight and 90 degree), and it has a switching mechanism to convert from inside circlip to outside circlip. Seem decently built. Cost about $25.

On the other hand, my bleeder setup is a piece of fuel line from Auto Zone along with an empty small brake fluid bottle. Seems to work ok, my lever is pretty stiff now, likes it a more direct connection to the calipers, but I haven't had the opportunity to road test it yet. Soon, I hope.

Anyone tried the speed bleeders, or the vacuum-type bleeder kits? Are the end results different, or does it just make bleeding easier?