dragonsgate
True Classic
I hate when that happens.
Rear Brake locking up
- Thread starter davejake
- Start date
Michael Oxman
The Journey Begins!
So I refurbished the calipers (inner rings and dust boots) and seated the pistons as far as they would go, but on my left brake the piston is not recessed enough to get the caliper over the brake pads. I gave the piston an extra few turns to ensure its fully seated and the ebrake cable was not yet attached when I tried to put it on. I'd appreciate any thoughts or suggestions..
Michael Oxman
The Journey Begins!
Continuing on, I found the post below from 2015 on another thread. I'll have to take the caliper back out and investigate. As mentioned in the post, it was hard to screw the piston back on.
Also, I noted when I put the ebrake cables back on they were partially "bowed" between the bracketing slots. I don't remember how they were when I took them off but I don't remember them as bowed, and perhaps this is indicative of the mechanism in the caliper not fully retracting. the ebrake lever in the cab is out of its holder so there's definitely no tension on the cable right now.
Also, I noted when I put the ebrake cables back on they were partially "bowed" between the bracketing slots. I don't remember how they were when I took them off but I don't remember them as bowed, and perhaps this is indicative of the mechanism in the caliper not fully retracting. the ebrake lever in the cab is out of its holder so there's definitely no tension on the cable right now.
rear brake caliper problem
Hi, the brake caliper ceased on, that bad that smoke came off the wheel and the pads were toast. I tried to wind it back but it was stuck so I removed it from the car and replaced it with a spare which was winding back pretty good. I replaced the disk/rotar and pads but the brake is still...
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Tom Ginefra
True Classic
The "bowed" outer line is perfectly normal and has no effect on the operation of the cable inside.
You said you "refurbed" the rear calipers... but did you dismantle them? Are you absolutely sure the e-brake plunger is correctly oriented and seated properly, and have you confirmed that the e-brake arm (and tapered key) is moving the plunger when it's rotated, before you repacked everything with the appropriate grease and sealed the rear boot back up?
Tom Ginefra
True Classic
Michael,
I just sent you a PM
I just sent you a PM
Michael Oxman
The Journey Begins!
Thanks for the reply Tom, and I will definitely take you up on your kind offer. For the sake of the thread, I did not dismantle the caliber, only replaced the inner ring and dust boot and cleaned up the piston. The piston is definitely moving when i manually squeeze the brake mechanism.
If you didn't mess with the pawl/lever mechanism on the back of the caliper and the lever is doing it's stuff now, and you can't screw the piston all the way in even when the cable is disconnected.... then that mechanism is not the problem. This is good news, becauseyou don't want to take that mechanism apart if you can help it - compressing the spring washers so that you can get the pawl back in is tricky.
You are pushing the piston in as you turn it, I presume? Silly question, I know.
By "inner ring" you mean the seal inside the cylinder of the caliper? At this point, I'd be inclined to unscrew the piston again, check the guts of the adjuster mechanism inside the piston for for free movement and no debris (but don't take it apart until you're sure you can put it back together again - it's not hard, but there''s not a lot of good documentation on how it's supposed to go together), check for messed up threads on the shaft, verify that the shaft is fully retracted, check for debris in the cylinder....
If that doesn't expose any problem, you might try removing the seal and screwing the piston in without the seal, see if it goes in all the way. It will be a lot easier to see where/why/if it hangs up without the resistance of the seal. If you do this, be careful with the seal or be prepared to buy another.
Michael Oxman
The Journey Begins!
Yea, I just did a rebuild with the standard kit. Cylinder ring and dust boot. It has definitely screwed in all it can and now just turns like it should without going in further. I'll follow your advice and give it a try.
Cratecruncher
True Classic
There is a ratchet type mechanism in the piston itself. If the ratchet is not working the piston can spin forever without threading onto the screw. You can try removing the piston to inspect that mechanism to make sure it is working properly.
Michael Oxman
The Journey Begins!
I think I got it - I took off the caliper and took out the piston - so tight it was almost impossible. I ran my finger along the inner seal that I replaced and felt it was not flush. I took the seal out and the piston screws right in, all the way, very easily with just two fingers, so I'm thinking there is some crust or gunk in the channel that I missed. I'll hit with a dremmel wire wheel. Fingers crossed.
I would be reluctant to use a Dremel or any other powered abrasive - much too easy to round an edge at the seal groove or otherwise mess up the cylinder, and the tolerances here are pretty tight. Find a pointy tool wth a right-angle bend and use it to clean up the groove like @Jefco says - nothing awful will happen if you scrape the bottom of the groove. FLAPS will sell you a set of picks for a few bucks, and one of them will either be right or can be bent to make it right.
Michael Oxman
The Journey Begins!
Thanks. Given your advice I'm glad the dremel wouldn't fit. I used my harbor freight pick set and the piston is in!
Before and After:
Before and After:
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Janis
True Classic
How can I check is e brake plunger oriented correctly?