"Black Hole" Blues

You may recall earlier in this blog that I removed the Clutch Master Cylinder to rebuild with a kit I bought in the mail. Well It was working fine, but randomly one day when I backed the car down the hill to turn it around to work on the passenger side it wouldn't slide back into gear. So after towing the car back into the garage we quickly diagnosed that the clutch slave cylinder was leaking fluid and not building pressure. So off it went to White Post. It came back, got re-installed, and the system was bled. After fully bleeding the system the pedal still would go halfway to the floor with no pressure, not good. So I figure the clutch master is now the issue, chances are the $17 kit from china probably isn't the best. So the master has to come out again.

Most automotive companies when it comes to designing hydraulic brake and clutch control system aim for simplicity and ease of maintenance, at least they did once upon a time. For example check out the location here in a CJ-5, it's so easy to get to, and the reservoir is right on top of the cylinder.

SAAB however, as usual threw convention to the wind and mounted their cylinders way down out of reach, because they know better. The master cylinders -both Clutch Control and Brake- in the Sonett are mounted right behind the pedals on the engine side of the firewall, down behind the trans-axle, beside the transmission, underneath the steering rack. The fact that I have to list 3 things that they're near should be a giveaway how impossibly difficult it is to get to the cylinders, never mind getting tools on them. This area is affectionately known among Sonett owners as the "Black Hole" as you put hands, tools, screws bolts, and anything else down there and they don't come back.

Since this is such a common issue Ashcraft sells an access door that allows you to cut a hole in the frame there to get tools on the cylinders but doesn't compromise frame rigidity. So I bought one of those, but it's a custom built part and he didn't have one ready in stock. So I got the instructions and cut the hole so I could go on and get the cylinder out and send it off.

So with the cylinder out off it goes to White Post to get rebuilt. Hopefully after it will let the car go back into gear and then mechanically the car is done.

Rebuilt Brake Master Cylinder

My brake master cylinder was leaking fluid back into the pedal box and was really really spongy on the few drives it went on. So since after spending close to 2 hours calling dozens of automotive stores I finally contacted the manufacturer who makes the rebuild kit for the cylinder, and they had of course discontinued it. So what was going to be a $20 part became a $225 rebuild to White Post Restorations in Virginia (http://www.whitepost.com/). I will say though that while it's expensive you get what you pay for it. The cylinder came right out of the box powder-coated, with the fitting re-tapped, all new seals and dust cover. It literally bolted on, we bled it and my brakes were rock hard. Plus any cylinder they rebuild comes with a lifetime warranty and you have any problem they'll rebuild it again for free.

Clutch Master Rebuild

Finally got the inside piston out of the master cylinder today. I had let it soak in PB'Laster for around 12 hours while I was at work but when I got home all the fluid was still sitting in the seal, it obviously hadn't penetrated the rust seal. So I got the idea of trying to put air-pressure behind the seal from behind to try and blow the piston out, I figured it's not letting fluid in so the air-pressure should build and knock it loose.

That didn't really work, even with the top sealed with duck tape and a seal around where I was forcing the air in. I put a piece of wood between the cylinder and the ground and banged it on there, that didn't work so I resorted to shielding the metal with another piece of wood and hit it with my big-ass hammer, still no movement. I sprayed in more PB'Laster and then sprayed air in to see if it bubbled, that meant the air was leaking out. It bubbled up a little at first but slowly bubbled over. Then I got the idea that if I was seeing bubbles that meant something was replacing the air in back of the seal, namely the PB'Laster. So I'd pump the air for a second let the bubbles stop, then pumped again. I got enough PB behind the seal and let it sit for a little while, this time when I banged the valve end (open end where the clutch pedal pushes) against the wood the piston finally moved. A few more bangs and the piston came out.

In the first picture you can see what the piston looked like before I did anything to it other than pull it out. Once it was out though I took it apart as much as I could, into about 3 or 4 pieces big pieces and started to remove the rubber seals that were basically sponge after years of dry rot and brake cleaner soaking. Once all the rubber was off I removed the plastic pinch cap from the back end of the piston, if the rubber there was solid it would have had to come off first. After all the rubber and plastic was off I took the wire-brush Dremel head to all the metal and removed a ton of surface rust from the guiding rod and other components that had caused such a problem in removing the piston. Once I was content all the parts were as clean as they were going to get I rebuilt the whole piston, new rubber boots and the tiny metal waster that goes under the pinch cap.

Then I turned my attention to cylinder itself, the cap was destroyed from all the grabbing it with pliers so I ground down the rough spots and smoothed out the edge. I wire-brushed the whole surface, bottom, and threads cleaning off the brake fluid that had turned to glue and sealed it so tightly. Once the top was cleaned I covered the threads, bottom, and holes with painters tape and then clear coated the surfaces that would be exposed to air. The actual cylinder got a similar treatment with the wire-brush cleaning and polishing the surface and then clear-coating the exposed parts to prevent more corrosion.

Then we built out own extended sanding rod and attached it to the drill to clean out the inside of the cylinder. If you're going to attempt this be very careful because if you mess up the seal inside the whole thing is just scrap alloy. We wrapped 1000 grit sandpaper on a drill-bit wrapped in duck tape. The paper wasn't held on tight, we counted on the paper trying to unwrap to do all the real work.

To clean out all the dust we'd created with the sandpaper I improvised a barrel cleaner with a screwdriver, duck-tape and a paper towel.

Quick spray of brake cleaner inside to get anything else in there, then we liberally greased up the piston with red brake grease and slide it back into the cylinder. Once it was in I screwed on the lid (complete with new rubber seal) and the hydraulic line to do a bench test that it would pump fluid. At first we had issues getting it to put out fluid, but once we primed the output end it sprayed like a champ.

So the master cylinder was finished and ready to go back into the car. A severely skinned and cramped hand later the cylinder was back in, with the new boot, the push rod was reattached to the clutch pedal and to the master cylinder. We bleed the clutch and now it had feeling, the car slide right into gear.

Clutch Cap Removal

My goal for this weekend was to get the clutch master cylinder apart. After 24+ hours of soaking in the PB'laster the cap wasn't any looser so I tried to soak it in brake fluid, brake fluid is pretty corrosive so I was hoping that it would corrode or revitalize the crystallized brake fluid that was gluing the cap stuck. No luck there either. We threw the whole cylinder in a vice, nailed the vice down to prevent slipping and cranked on it with a pair of channel-lock pliers. Still no movement. So we tried an old mechanic trick to breaking loose rusty parts: temperature cycling.

The idea is that metals (like all matter) expand at higher temperatures, so you heat the metal so that the hole opens up more and you can break the piece loose. I cycled the cylinder by letting it air cool a little after it got blasted by the heat gun (at up to 1300 degrees Fahrenheit) then dunked it in warm water in an attempt to quickly contract the expanded metal to break the oxidization loose. After three or four rounds of 15 minutes of heating, then 5 of air cooling  then dunking it in the water, I left the heat gun on the cylinder for 45 minutes, grabbed it with a pair of pliers and dunked the cylinder body only in the water , making sure to keep the cap out (I would not recommend this unless all else fails, the temperature shock can crack or shatter the metal you're working with).

After it cooled in the water for a  few seconds I threw it on the vice, tightened down on the cap and turned. Finally I got some movement, a few more cranks and it was loose enough to remove with just my fingers (after cooling the cap of course).

I left the cap off and soaked/sprayed the whole cylinder with brake cleaner and set it aside to break down anything inside so when I go to rebuild it I won't damage it when pulling out the push-rod.

Clutch Continued

Today I managed, after a considerable effort, to remove the clutch master cylinder from the car. The cylinder seems to be something of a weak spot for Sonetts because everyone seems to have issues.

So here's what the master cylinder and accessories looks like:

I found out why the cylinder isn't delivering any fluid to the slave and transmission....

There's your problem, unfortunately I wasn't able to get the cap off my cylinder so I soaked it in PB'Laster in attempt to break some of the corrosion. I scrapped out the crud clogging the hole so the PB could really get in there. Still no luck though regardless of how hard I tugged on the cap with pliers it will not come loose. Im leaving it soaking in the PB overnight and I'm gonna keep looking for tricks online for removing that cap.
If I cant find anything Im gonna have to send it off to get refurbished for 230 frikken bucks,not including shipping. I really don't want to do that.