Tuesday, April 7, 2015

Belay My Last.

... or maybe not. The last thing I was crowing about was that the old Volvo now runs and drives; and yesterday I dared to find out if it would run and drive further than 100 yards from the relative safety of the garage. Which it most certainly did do, and I had a fine time zipping down to the post office, then stopping on the way home for a tasty celebratory hop soda.
The part that wasn't awesome was that I could feel the brakes dragging a bit. Not a whole lot, but a bit. Our driveway has a mild incline to it, and the car would roll down that, so I convinced myself that the brakes were just bedding in and that once the new pads became familiar with the old rotors and calipers that all would be well.
Trouble is that I usually know better than that. This was the kind of hoping one does when one does not wish to undo a fair amount of already accomplished labor. Like maybe if I'm nice to strangers and I really really hope that this one time I have a car with dragging brakes things will turn out completely different than the several other times I've had cars with dragging brakes. I was in denial.
To support my denial, I thought about what else might cause both rear brakes to stick while the front brakes were working exactly the way I wanted. I thought about the dual master cylinder and what might make one circuit not work properly; I thought about the proportioning valve and whether it might have some internal flaw, and I thought about some errant piece of debris that may have found its way into the brakeline - somewhere upstream of the T fitting - and was now acting as something of a valve and was preventing the release of brake fluid away from the calipers.
Then I did the thing you should never do when you have a symptom of any kind. I looked at google.
First thing was to remove the brake pedal actuating rod from the master cylinder to ensure that nothing was possibly activating the master. Wheels were still stuck. Next, I removed the flex line that connects the hardline on the belly of the car to the T on the rear axle. No change. Then off came the T fitting itself:
These look better on the car than on the floor.
Of course, because I've got racecar on the brain, I'd used the fancy (that is, not particularly affordable) ATE Blue Racing Brake Fluid Suitable For Rockets in the brake system. It's a very nice color and if it didn't feel like watching money burn I might not have minded seeing it drain into a pan under the car. I don't believe it's wise to reuse brake fluid. Even if it came out of a new container and went into a new system and then drained into a clean glass pan. Phooey.
I still couldn't turn the rear wheels by hand. Just to be absolutely certain that there wasn't a clog in the line, I applied pressure to the brake pedal. A LOT of fancy expensive even-stops-the-space-shuttle brake fluid squirted out. It isn't blocked. The good news is that I don't have to replace a brakeline nor the proportioning valve.
The crappy news is that I get to rebuild the rear calipers. I really don't like doing this. Mostly because it means dealing with gross old brake fluid and rusty crap that's hard to take apart. I'd be happy to bolt on some freshly rebuilt calipers, though, so I called Mike Dudek at iRoll Motors to see what he had on hand. The supply seems to be flush with right hand calipers, yet void of lefts. Or maybe I've got it backward. But the point is that one side is easy to find and the other is not. iRoll will rebuild your calipers for you if you like, or they can sell you rebuild kits and you can deal with the mess yourself.
I chose the latter, as that way I have to wait only for the kits to be delivered before I can get busy putting the stuff back together instead of waiting while parts are shipped from here to there and back. I made this decision before I relearned how yucky old calipers are. If you have to get this done, send 'em in.
These came off:

... after removing one of the dust covers, I found it to be full of little rust crumblies. Hard to tell on a wood bench, but that dusty stuff in the middle of the pic is a sample of the offensive material:

Recurrent theme: there's a smart way to remove the pistons, and there's the way I went about it. The smart way is to leave the calipers on the car and use the force of the brakes to push the pistons partway out of their bores within the caliper. But I was so busy wishing reality would bend to my whim (I do that a lot. It never works.) that I'd disabled the brake system and it didn't seem worth the trouble to put it all back together just so I could take it apart again.
Three of the four pistons came out pretty easily. The last one, though, did not. A self tapping screw into the center of the piston provided something to pry against, and a torch helped loosen things up. Good news: neither the old brake fluid nor the penetrating oil appears to be particularly flammable [Do NOT attempt to verify my findings! No no no!]. This one took twice as long as the other three combined:

There's that self tapping screw. DON'T try this at home. Do not.

After the pistons come out, the O-rings can come out. That part's easy. The thing that annoyed me is that they all look pretty good. And the pistons, which I expected to be covered in rust, also really look pretty good (not counting the ends that I abused with vise grips and similar horrible stuff).
Those are the 0-rings on the left. Inside the silver cylinder, there's a little groove into which one fits.

 ... and they're apart:

... and though they don't look much different, the bores are now nice and clean and the passages are clear and the grooves are without rust or debris:

For posterity, I guess, I'm including a pic of one of the hardlines from the rear axle. It's just a dang brakeline. But to see it lying on the floor, unloved, and draining $16 a quart fluid onto the ground makes a statement about where we are in the overall process of Pretending To Build A Racecar.

The rebuild kits are en route, and most of the rest of the car is where it needs to be for initial road testing; so once I can get the calipers back together and on the car, we should be back in business.

Parts sourced for this installment were ordered from iRoll Motors. An excellent resource for the vintage Volvo owner: http://www.irollmotors.com/

Next week: calipers go together so beautifully that we all weep a little and the car assembles itself like that super badass liquid metal dude in Terminator 2.

'til then --

1 comment:

  1. It's when you start saying "belay my next" that you know you're in trouble.