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Katie-Nicole: One way to get procedures on this site is to type in to the SEARCH box various descriptions of what you want. You may have to plow through a lot of answers but many prior posts talk about this. Some disagree with each other so you and your dad have to be your own judges.
For practise on my technical writing skills, and in my opinion of how the various manuals (you should buy a Bentley's) should do it, here's what I remember from the two I've done:
1. It doesn't always "take" in that the new rubber cup sometimes fails to properly expand and grab the inside of the bore; but this may well be due to imperfect bleeding out of the air in the system. It doesn't usually happen.
2. Bleeding is the question about which you will find LOTS of opinions. I have done it with help of a "poor man's bleeder" (look up under search) using a bicycle inner tube; plus lots of old-fashioned leg muscle pumping up of pressure, followed by quick release and re-tightening of bleeder screw.
A couple of helpful or necessary tools: A crow's foot 13mm (1/2") flare nut wrench helps loosening and tightening flare nut on line into master cylinder. At least a standard 1/2" flare nut wrench to break it free first.
A pair of inside circlip pliers with angled tips, to release and reinstall the clip that holds the piston, spring etc. inside the bore of the cylinder.
A vise that opens at least 8 1/2" or 9", to hold the works compressed inside the cylinder while you reinstall the circlip. Or an arbor press (I own an old fashioned one that makes lots of jobs easier.) Or, maybe a woodworkers bar clamp or pipe clamp. Or two people, one strong and steady handed to hold the piston depressed inside the cylinder, the other steady handed and deft, to get the tips of the circlip pliers into the holes in the circlip and compress it and slide it into the groove down in the bore, while the other one holds everything still.
FIRST, remove the cylinder from car. It's bolted to the firewall, a little below and to the left of the brake master cylinder:
l. I think first I popped the vacuum hose out of the brake booster to make a little room and get better vision.
2. Loosen or remove the sheet metal screw on the clip holding the metal line (from clutch master cylinder to clutch slave cylinder) to the left inner wheel well. This frees the line up so you can get it out of the master cylinder. It has a Torx head; might just want to grab it with Vise Grips first to break it free, as it often rusts on the threads.
3. Detach hose that feeds hydraulic fluid from brake reservoir down to clutch master. It comes out of a little side pocket of the main brake fluid, so if it leaks out you don't drop to danger level for your brakes. I found it easiest to remove this from the reservoir, compressing the spring clip that's on it with a pair of vise grips and sliding it down, then working the hose off the nylon nozzle off the reservoir, then quickly sliding in a cut-down paper coffee cup to catch the fluid that comes out, so as not to make such a mess.
4. Set a piece of cardboard or an old rug scrap down on the ground next to the driver's door, open the door, and sitting on the rug, back to car, facing towards right shoulder and twisting that way, with a good light, reach up and slide the spring clip off the pin that holds the clevis or yoke at end of master cylinder push rod to the clutch pedal shaft. It's got kind of a V-shaped space at one end where the two sides of the clip end; pry that open a little and that lets the clip slide off the pin. Push and pry the pin out the other side of the yoke. Set aside. I can do this barehanded and without looking but prying with a screwdriver might seem better to some.
5. Go back under hood and loosen or remove the flare nut and line that lead away to the slave cylinder. At least loosen it now as you don't want to be prying against an unattached master cylinder.
6. Now, back on your rug and head under the dash, remove the two 13mm (1/2" nuts that hold the cylinder to the firewall. Saab uses aircraft nuts, with nylon inserts, so they'll need a wrench all the way off. Sometimes the stud comes loose from the master cylinder instead; if so, count yourself lucky as it unscrews easier.
6. Now back under hood if you didn't fully remove the line to clutch, and finish undoing the flare nut, pulling line towards front of car as you go so it's easier to get it out. Remove master cylinder, with cotton-covered rubber feed line attached, and head for a warm, well-lighted clean bench to do the rebuilding.
REBUILDING:
I got my kits from the local Napa, came with the Worldparts designation, and I guess they're for other applications as well because there were a few non-pertinent spare parts inside. But they were cheap, I think $12 and change, and they had one on the shelf.
1. Clean the outside off, and pump and tip it to drain any old fluid onto newspapers or something. Pry the rubber boot off the cylinder, leaving it on the bushing that slides on the push rod. Turn it inside out to get it back out of the way, and using your circlip pliers, release the circlip spring ring inside the bore and pull it out. The guts should pop out onto the bench. A ring made onto the push rod assembly holds its ball end in. Leave the circlip right on the push rod.
Other two parts are the piston with attached seal and sealing rings, etc., and a long spring. I've read on here reports of that spring breaking, and it doesn't come in a kit, so if that's bad you need a new or used master cylinder to proceed. (But if the pedal pops back up all right before you start, the spring is probably fine and you can go forward).
From here on, pay attention to what's where and how it is oriented, so it all goes back together right.
I use rubbing alcohol to wash out brake and other hydraulic system cylinders when I rebuild. It's cheap and dissolves brake fluid away cleanly. Compressed air cleans it all away and bloows dry but isn't needed.
I just use brake fluid as reasssembly lube but special pastes are sold for this too. Note Saab calls for DOT 4 grade brake fluid, more expensive than the common DOT 3, higher boiling point I think. To do things right use DOT 4.
Once you have cleaned the cylinder bore you need to look down it, with light entering, to make sure it doesn't have bad pitting or rust that would mean it's not a good candidate for rebuilding. But if it was just working fine and then quit, it's probably good. Rust more often happens in a car sitting a long time. (Brake fluid absorbs water over time.)
There are brake cylinder hones, and you can rent or borrow them at some auto parts stores. I've made one by wrapping a dowel with wet-or-dry sandpaper, just enough to go around, and Elmer's gluing it on, then waiting a while, and swabbing the bore with that. Rinse clean after honing. Honing is nice but I don't believe necessary.
The kit I got had an end cup with a hole in it, and also one with no hole. That was the main extra part. It also came with skinny flat washers, a brass one I believe that works as a one-way valve behind the cup, and maybe one extra one, (larger, one of the mystery extra parts), and a nylon split pop-on cap that holds things on the piston.
Stick a screwdriver blade into the slot on the original nylon cap on the piston and it should open it up enough to remove, then remove the end cup and brass washer. Clean off the piston thoroughly, including making sure the drilled passages behind the brass washer are clear. An old toothbrush helps here, also compressed air.
You need to remove one of the old rubber seals, as I recall by stretching it over the piston. New one goes on just as you removed the old one, lubed with fluid, so stretching the original one off instead of cutting it makes sense to me as it teaches the mechanics of handling before you need to proceed with the good one. It doesn't look as if it would stretch but it is tough and flexible and it will.
Make sure to see which way it faces and put the new one on the same way.
Using things to pry here is risky cause you don't want to nick the piston or cut the rubber at all. Plastic knitting needles, or brass picks meant for this sort of thing, are good tools but even a stiff big paper clip straightened out can work.
Then install the new brass washer, the end cup, and push the new nylon cap on the end. It goes on like an old fashioned poppet bead, no need for a screwdriver to install it.
The kit also comes with a replacement for the outer boot that you turned inside out when disassembling. But on my cars, the 15 year old original boots looked like new still. One of them, I cut off and stretched on the kit replacement, only to find looking at it less than a year later that it had age cracks all over its surface. Cheaper rubber by far than Saab's. Though it doesn't really seal much dirt out, I'd rather have kept the original and I recommend that to anyone else, if it looks good.
Now, applying brake fluid or assembly lube liberally, you put the whole mess back in the bore, spring first, facing in correct direction, then the piston, then the push rod and its collars. I put a tiny dab of plumber's silicone grease on the ball end of the push rod but it's not necessary.
Two people method, push it all home, get circlip pliers into holes, squeeze it down and get it in the bore and seated. One-man method, push it all home, get it into vise or press or bar clamp, (or between two 2x4 blocks screwed down to a piece of plywood) then take pliers and seat circlip.
Flip outer boot back over and reinstall in bore.
REASSEMBLY:
1. Put it back through firewall. Some recommend starting flare nut from line at this stage so you can wiggle cylinder around and make sure of going in straight to start threads easy. Then bolt it back up. I replaced the aircraft nuts with standard 8mm metric so it would bolt back easier. Then if you want slip clevis yoke over shank of pedal, and push pin back through and attach clip.
2. Reattach feed hose to reservoir, and compressing its tabs with pliers of vise grips, slide the spring clamp back up to the top.
3. Read up on this site's postings on bleeding clutch. Most recommend flushing out all old fluid as it's probably got lots of water in it, besides black crud from worn seals etc. The main good advice I recall is to leave the flare nut at master cylinder loose when first adding fluid and pumping to bleed, to get fluid into master cylinder, and also to crack it later in bleeding, to remove air that tends to rise up the line.
The bleeder screw on the slave cylinder uses a 13mm socket, though you can't go straight onto it, or just a 13 mm wrench. It's visible on the side of things towards the front of car, at edge of black plastic clutch cover.
(Follow the line and it's just above where that attaches to slave cylinder.)
Some back bleed, forcing new fluid in the bleeder nipple through a clear plastic line attached to a squeeze bottle full of new fluid. If you do this, do it first to purge dirty fluid before even reinstalling the master cylinder, till clear new fluid flows out at flare nut end, then do it again after master cylinder is attached.
Bleeder screw doesn't need to be set down tight when bleeding, just twisted till on its seat. Can do it almost by hand and be tight enough.
I bled the first one alone in a field, pumping the pedal like crazy several times with bleeder closed, jamming a two-foot 2x4 between the seat lip and the pedal, running around front and cracking the bleeder, then repeating, till finally I got some pressure. Then with bleeder cracked a little bit I pushed the pedal a few times and felt solid pressure, closed it off and I was golden.
I think pre-bleeding master would make it easier, also I think I'll try back bleeding as described above if there's a next time.
Don't let fluid drop too far in reservoir as you pump.
At end, top up brake fluid reservoir to full mark, and don't forget to retighten screw holding line clamped to inner fender well.
posted by 64.222.242...
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