Brake Problem '83 GS550 (suggestions neeeded by Tuesday)

[Guest]

I'm having a brake problem. I recently took my bike to a shop for a brake caliper rebuild. When I got it back I could haul the lever to almost the bar before I got any pressure. The dealer said I needed a master cylinder rebuild. For 28$ I had them go off and do it.

When I got the bike back after the master cylinder rebuild I'm getting the same effect. No pressure until the brake is almost at or touching the bar. I had another place look at it and to test the master cylinder they clamped off the line at about 7 inches down the line. Ta Da OMFG we've got very nice tight pressure... nothings leaking and it all seems OK. As soon as we add the calipers back in we've got nothing again.

This second place suggested the calipers or the antidive system. I attempted to clamp off the anti-dive and do the same test but the lines to the antidive are rock solid (I could squish them but not clamp them off.

What in a caliper rebuild could possibly cause this? Is it maybe the antidive has gone FUBAR?

Any suggestions on what to start looking at?

[hampshirehog]

Sounds like they just need bleeding. If your AD was ok before the caliper rebuild it won't have gone overnight.

[GQROD]

I'm having a brake problem. I recently took my bike to a shop for a brake caliper rebuild. When I got it back I could haul the lever to almost the bar before I got any pressure. The dealer said I needed a master cylinder rebuild. For 28$ I had them go off and do it.

When I got the bike back after the master cylinder rebuild I'm getting the same effect. No pressure until the brake is almost at or touching the bar. I had another place look at it and to test the master cylinder they clamped off the line at about 7 inches down the line. Ta Da OMFG we've got very nice tight pressure... nothings leaking and it all seems OK. As soon as we add the calipers back in we've got nothing again.

This second place suggested the calipers or the antidive system. I attempted to clamp off the anti-dive and do the same test but the lines to the antidive are rock solid (I could squish them but not clamp them off.

What in a caliper rebuild could possibly cause this? Is it maybe the antidive has gone FUBAR?

Any suggestions on what to start looking at?

1-A caliper rebuild in most cases is super simple. It's only a matter of replacing a rubber dust boot that goes over the caliper piston and the seal if any the piston slides through kind of like a fork seal, and a simple large circlip like spring to hold it.

2- In extreme case the pistons are machined but this is rare.

3- I'm having the same problem with my front brake but i have not touched the brakes since i bought mine over four months ago and i think it needs to be bled.

4-This is my first shot at a braking system with anti dive so i will have to check the manual and see if there is special way to bleed the brakes.

5-Try bleeding it first if this does not work then going with stainless steel braided lines will definetly firm them up.

6-Are the pads old? chances are because it is not a power brake system like cars as the pads wear the pressure exerted is less and more noticeable.
Hope this helps.

[skreemer]

all 4 front pads are brand spanking new...

The shop I went to today bled the brakes (I watched them this time) and those guys seemed good to go. Even before today's guys got a hold of it the system had been bled at least once before by the other guys (I don't trust em though)...

[Planecrazy]

Incidentally, Steve, you might want to have your credit card company reverse the charges to the shop for the amount that they charged you to make the bike worse than it was before you brought it in. They'd be hard-pressed to justify their charges, considering the vast amout of time they had your bike and the unsatisfactory result...

Good luck with it!

Regards,

[Planecrazy]

By the way, as a stop gap measure couldn't you use the brake parts off of one of your other bikes? Maybe not the perfect solution, but it should get you safely on the road if you still have all the pieces parts you had before the move to Iowa.

Regards,

[skreemer]

yeah two issues... #1 I don't have a credit card so everything was cash...

#2 when I moved out of my house I had no where to store all those bikes.. they all got sent to Greg (he owned most of them) or they were salvaged... (comedy option#3 I left the 84GS550ES in the drive way too long and the city took it after I moved out)

[Nessism]

Did the pins in the caliper get greased so the caliper will slide properly? If not, the caliper will not slide properly which can cause the same symptom.

[GQROD]

Did the pins in the caliper get greased so the caliper will slide properly? If not, the caliper will not slide properly which can cause the same symptom.

Greased with anti squeal? i know this is used on the backs of pads, is this what would be used?

[Nessism]

You need caliper grease. It's a high moly, high temperature grease. I bought some at NAPA.

After you grease the pins, slide the caliper back and forth on the pins to make sure it slides smoothly. Some times the holes in the caliper bracket wear which causes binding.

Also, when you get around to bleeding again, crack the banjos a little to make sure air is not trapped.

Good luck.

[GQROD]

You need caliper grease. It's a high moly, high temperature grease. I bought some at NAPA.

After you grease the pins, slide the caliper back and forth on the pins to make sure it slides smoothly. Some times the holes in the caliper bracket wear which causes binding.

Also, when you get around to bleeding again, crack the banjos a little to make sure air is not trapped.

Good luck.

Thanks a million!!

[skreemer]

Thanks I'll give that a shot.

[Griffin]

I had a similar thing happen to me after rebuilding the calipers on the (formerly mine) 550ES,a nd also my 700ES. I think that these bikes are harder to get the brakes feeling good once the system's been dismantled because of the ant-dive plumbing.

There is a psecific procedure in the service manual for bleeding them. Was it followed?

I'll post the procedure later today if you don't have it.

[skreemer]

The second crew and I followed the bleeding procedure in the Haynes manual... Left AD unit bleed then left caliper... right ad unit and then right caliper... They did it twice yesterday and I did it once today... There were no bubbles coming out of it...

Question - Id I have a caliper on one side that's run out a bit and seized and won't retract will that give me about the same symptoms? (All the fluid rushing to one caliper?) (seized AD possibly?)

They are feeling much better today... though not as good as what I'm used to.

[first timer]

just unplumb the anit dive, and run the lines right to the calipers. just reuse the banjo bolts with some washers as shims to cap the holes. As along as you don't remove the dive units from the forks no fork oil will leak out. To be on the safe side might want to put your old pads back in while you are bleeding incase you spill brake fluid on them....

thats how i am running the 83 1100 forks on my 1k. they are working fine for me, plus you are running progressive springs right? if so you don't need that silly anti dive system.

you can also try bleeding the system up by the master cylinder, just presureize it thn crack the banjo bolt that connects the brake line to the MC, some times air gets trap in there. Just use a rag because it can get messy.

-Ryan