Thursday, May 27, 2010

The great brake rebuild project

Today (Weds the 26th) we pulled the bus into Darrel Ozmun’s shop east of Nipawin.  We were up here a couple of weeks ago at which time we ordered some brake parts and now that the parts have arrived we’re back to put them on.  Of course nothing ever goes as easy as we think it will.

I put new shocks on just 2-1/2 years ago now but you’d never know it from the condition they were in so we ordered 10 of NAPA’s finest.  The last ones came from Prevost Parts – these are Gabriels, for whatever that might be worth. 

Les flailed away at the brake drum and I kindly stayed out of his way or occasionally rotated it so he could hit a new spot with the 10 pound sledge.  Finally it separated from the hub and then it was (the other) Bob’s turn to do the actual brake work. 

It turned out that Al’s NAPA bus expert wasn’t completely expert.  He managed to ship us springs that flat out wouldn’t work and the seal kits that he shipped for the camshaft are marginal but will likely work for our purposes.  We’re hoping that the right springs will arrive tomorrow afternoon and, as usual, we forgot to order seals for the hubs so we’re waiting for them too.

The running gear on the bus is massive.  Every time I have some of it apart I am reminded of just how overbuilt it is.  The last time we had the wheels off one of Darrel’s men built a special tool to tighten the pre-load “sleeve” against the bearings.  (I’m not sure what to call it – normally there would be a thin nut holding the preload but on a Prevost there is a fairly heavy threaded sleeve followed by the standard nut which only serves as a jam nut in this case and which is further held in place by the traditional bent tab washer.)

We had to burn off one of the bolts that holds the brake drum to the hub.  They were all pretty well seized in but one absolutely wouldn’t come loose so we had to burn the head off it.  The best way to deal with a situation like that is just to put an oversize nut on the stud and weld inside the nut.  The welding heat expands the stud which helps to break it loose once it cools off again and the nut gives you something solid to put an impact wrench onto.

Its so nice working in Darrel’s shop because he has absolutely every tool known to man.  Two weeks ago when we were here I said something about pulling one of the drive tires and taking it to a tire shop because I had a leaking valve stem.  No problem – turns out they have a truck tire machine that is fancier than anything I have ever seen in any tire shop.  Today Les took the hubs to their steam cleaner and then brought them back sparkling clean. 

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