| Sanity check on rear brakes [message #307296] |
Sat, 17 September 2016 17:57  |
habbyguy
Messages: 896
Registered: May 2012
Location: Mesa, AZ
Karma:
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So, I did a brake/bearing service on the rear four wheels...
1) New 1-1/16" wheel cylinders on the middle bogies, one new 15/16" cylinder on the rears (the other one was fine)
2) New "Thermo quiet" brake shoes on all four wheels
3) Cleaned and re-packed all four wheel bearings
4) Cleaned and lubed (as much as possible) the parking brake cables - they were pretty sticky before, all seem to move OK now
5) Adjust the brakes by turning the adjusters to "really dang tight", then backing them off to where they're easy to spin by hand, and are obviously "free" at at least one point in the rotation (they pass the "ring test").
6) Gravity bled the brakes - I'm sure I still need to do a good old-fashioned "real bleed", as the pedal is a little soft, but gets really stiff before it hits the floor.
Took it out for a spin, and stopped after a couple miles of stop and go driving, and all the drums were warm, but none were really hot. Ran the coach up and down the freeway a few miles, and did a few "both feet panic stops" from speed (~50mph, down to probably 30mph), and one or two 35-0 full stops. All this was in the last 1/2 mile of driving.
Got it backed into the warehouse, and checked the temperatures of the drums. The two on the left side were nice and warm, but I could touch either of them with my finger, lightly (no way I could leave my finger there though).
The two drums on the right were well over 212° based on the "spit sizzle test" (no fingers involved). The middle wheel drum was obviously hotter than the rear wheel drum.
I jacked up the right side, and with a stiff push with my foot, the rear (cooler drum) wheel would rotate about 3 revolutions before stopping. The front (hotter drum) went around 15 times. The bearings both feel good with just the tiniest bit of discernible play when you push/pull on the wheels.
My guess is that the middle right drum is hotter because it's working better than the others, which I'm guessing might have something to do with less contamination on the pads and drum during reassembly (it was the least fiddly of the bunch), and that the others will "come around" as they're used and bed in. Or possibly, there is air in the lines on the other "cooler drum wheels"?
Anyone out there agree / disagree with my SWAG?
Mark Hickey
Mesa, AZ
1978 Royale Center Kitchen
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