Clingy front calipers

[buickyouth]

I may have to break up with my front calipers after the ess that they pulled on me today on LSD (Lake Shore Drive). I think they're just too clingy for me.

When I picked up my bike about a week ago, I noticed the front brake pads rattled. I have posted about this problem (view thread) It's been on the cooler side weather wise here in Chicago until today.

When I took the bike out of the garage and started out, I realized that the pads had stopped rattling. I was pleased until the bike started slowing down on LSD. I didn't think that I had let up on the throttle, so I opened it up a bit more and it was still slowing down. I pulled the clutch in and the engine screamed while the bike lurched and almost bucked me off. I let it back in gear and pulled over.

When I had it in neutral, and stopped the pads were siezed on the rotor. There was no moving it and I was still in the right hand lane of the 'Drive.'
(lucky I was wearing a red shirt) I used a wrench to open the bleeders and release the pressure on the system. I got the bike back home alright, but I'm at a bit of a loss as to exactly where my problem is coming from.

As far as I can speculate, the master cylinder is not operating properly. I bled the system a couple days ago to try and stop the rattling. The fluid level was really low. So, I added some. My thought is that the change in heat today caused the air or brake fluid to expand and push the pads in a little too much on the rotors. From there the added friction caused heated the pads, calipers and fluid even more which caused the pads to almost lock on to the rotors.

My question to you guys is how far on or off base am I in thinking that it's the Master Cylinder? Has anyone else experienced anything like this? What other places might be the issue?

As always, gentlemen, drop that knowledge on me.

[randy]

OKAY, here goes my 2 cents.

Being that your pressure released with the bleed tells me that your calipers are OK. They relaxed with the reduction in pressure. I would look further up the line, either at the lines themselves or the M/C

Air in the lines will never cause lockup. Air will do excactly the opposite, cause spongy brakes because air is compressable.

Something mechanical is keeping either the fluid from relaxing or the caliper piston is sticking. Do a teardown of the M/C. Also chnage the brake lines. I have had very old lines clog up on me in the past.

The lining will begin to break down and the residue will clog the line. The pressure of applying the brake will be able to overcome or move the clog, but the returning fluid won't have enough pressure to. This was the solution of my mystery sticking caliper with a seemingly good M/C and seemingly good caliper.

If both of your calipers are sticking and the M/C appears OK, I would suspect the main line between the caliper and the union. If it's just one, then the problem is isolated to either that line or that caliper.


HTH.

Randy

[mitch]

Spooge hole

Randy is right there is a hole thats plugged in the MC, Go to the maintenance section and click on brakes . Your answer is right there with pic and descripitions on how to repair ...............MITCH

[chevy45412001]

sponge bob spooge hole

in all the fixes for the cleaning of the spooge,it sez to take off the plastic bottle on the mc. Mine is one pieace aluminum (xj) i think i found the hole but very hard to get to,any tips for us xj guys or just try harder? sorry to cut in on your post buick.

[Pat Kelly]

I used a piece of guitar string (steel) to clean my pressure relief hole (spooge). Don't stand over it as the fluid and gung clogging the hole can come shooting out.

[randy]

Guys, Also,

Either remove your tank or cover it with a plastic garbage bag & rags to prevent brake fluid from contacting and melting the paint.

HTH

Randy

[ratbyk]

Brake Drag or Lock up

There are 2 holes(ports) from the master cyl reservoir into the bore of the master cylinder. The larger one(closest to the lever) allows fluid to keep the system topped up. The smaller one called the compensating port allows excess pressure that builds up in the system to return to the reservoir. The fluid in the system will expand and increase pressure putting the brakes on as heat builds up. This expansion must be released or it will continue to build until the calipers lock up.
Either the compensating port is plugged with spooge, or some other foreign material or the brake lever has been adjusted so far in that the main piston Assembly cannot return far enough to uncover the compensating port.
As warned previously, if you do prod it open with an ice pick or wire watch your eyes and painted surfaces. It will squirt or spit back with considerable force.
Ken/Sooke
78E Ratbyk
82 FT500 "lilRat"

[ratbyk]

Further on brakes

If any petroleum based fluid (oil) is allowed into the hydraulic system the first thing that happens is the rubber cups that form the pressure building in the system will start to swell. The next thing that happens is that the swollen rubber cups start to block off the compensating port not allowing the returning piston assembly to uncover the compensating port. Brakes start to drag. Heat starts to build and the self destruction cycle starts.
Ken/Sooke
78E Ratbyk
82 FT00 "lilRat"