Remove the Rear Brake Caliper Without Dropping the Rear
Remove the Rear Brake Caliper Without Dropping the Rear
Loren
If you see puddles underneath the rear end directly under the rear calipers
and it looks like hydraulic fluid --.it probably is. Both of mine developed
leaks at about 120000 miles at the same time. Probably seals, but I prepared
for a complete overhaul and purchased stainless steel piston replacements and
seal kits. But as usual there was more to be replaced for when I moved the
calipers to the bench and blew out the pistons with compressed air there were
bright areas on the cylinder walls. One recommendation was to use crocus
cloth to gently remove the wear--but I really couldn't see doing an experiment
when so much time went into removal (8 hours) and replacement would take 16
more including adjustment of the parking calipers. So, I returned the pistons
and did a rebuilt exchange for $200 per caliper. They come complete with pads
but no crossover pipe. Use your old ones. So far after 3 weeks there are no
leaks and the brakes work fine.
- Prepare for removal and follow Kyle's account of replacing the
differential output oil seal. Recommend loosening the hub joint cover hose
fastener and pushing the hub joint cover out of the way in order to see how
the parking calipers are mounted with pivot bolts through the main calipers.
I found that the pivot bolts were 7/16 ". I had to remove both hydraulic
fittings feeding the brakes and used 11 mm --be careful, and use lots of
liquid wrench because the pipe flare bolts are rather fragile and round off
easily.
- The bolts holding the caliper are 5/8" and only an offset box-end wrench
will do the job--perhaps one of those ratching box-end types would be useful
because there isn't much room for wrenching. Now if you are prone underneath
the rear axle here is a trick for breaking the torque on the left side--use a
jack with a wood block to jack up the wrench handle. On the right side simply
pull down with your weight! The parking calipers slide out the rear of the
car around the disc, while the main calipers slide the opposite direction.
- If you are ready for the replacement either with a rebuild (like me) or
your own parts kit in place--please check the parking brake for proper auto-
adjustment operation. To be safe plan for manual adjustment by removing the
cotter pin and devising a ratching screwdriver to turn the long bolt holding
the small caliper and large caliper together--then you can adjust while
everything is back in place. This is still not a easy task and I used a 5/16
mini-ratchet with a flat blade bit to fit. I also used safety wire instead of
a cotter pin because it was easier to work with. Difficult to align the hole
in the bolt with the hole in the housing but with mirrors it can be done.
Found a good description of the hand brake with details from an old series I
factory manual.
- Pause for mental reflection: the tech manuals say that the discs must be
centered within 0.01 inches of each main caliper. Well now, I figured that
rebuilds couldn't be too far off and if replacing the disc it probably is more
crucial. The scheme for disc centering requires balancing the shims between
the differential and the caliper mounting flange--another endless task. Check
the clearance when reinstalling the main calipers they should clear the old
disc easily.
- When replacing main calipers install the top bolt first--then align the
bottom one and install--this is all easier said than done. On the parking
caliper be sure that the pivot bolts go through the holes--they can slide in
without hitting the holes because the threads are only at the tops--look from
the side view to insure proper setup. Adjust the parking brakes to just
touching the disc before tightening the pivot bolts and remember to get the
brass retraction fingers in the pin holes as well.
- Attach brake lines--careful again, get both ends started threading a
little before all the way on either flare nut.
- Bleed brakes, I used a hand vacuum pump on each bleed screw.
- Start engine and apply brakes--they go all the way down initially, but
should built up and stay hard. Check for leaks.
- Re attach hand brake cable and check for adjustment.
- Return old calipers and get core refund and brag about your expertise to
the parts boys. Just ask Kyle or myself on how good it feels to have finished
this job. Or ask for help anytime.
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