I checked the flex line for ballooning too.
flex lines (all 4)
I am very convinced that your problem is in the rear drum brakes. They’re likely not adjusted properly. Even though that parking brake has never worked too great, now would be the time to GET IT to work great. Clean the inside of the drum brake assemblies out, and maybe even replace the adjusters. With the drums adjusted correctly, you should feel a slight drag when turning the wheel with the rear end raised.
A proper rear brake adjustment will do wonders for both pedal travel and braking effort.
-Matt
Consider this. Find a seldom travelled gravel road and at low speed, 5+/- mph, slam on the brakes and come to a stop. Get out and see if all 4 wheels have pushed the gravel, indicating that the wheel was locked up.
I have strong suspicions about the rear brakes too. The adjustment is good though, the shoes slightly rub the drums when the brakes are off. The parking brake adjustment is correct also and I am going to take a sander to the shoes and drums next chance I get. I don’t know if that will help though because they were not very effective even when they were brand new (thats the replacement drums, shoes and wheel cylinders last year).
Good idea, this is something that I have not done, and I have a dirt road right across the street. When my son gets home from work tonight, I will do just that, he has the car today.
Thank you all for the comments so far. I know I keep answering with “done that” or “tried it” and other words to that effect, but I’m hoping someone will come up with something I have overlooked.
This was humbling for me to ask for help because I think I’m pretty good at these. People ask me for help, know what I mean. Obviously there is something that I have yet to learn (ha ha).
Yesterday, I was at the hobby shop getting the tires balance and there was a guy there that had gotten in over his head with his Honda’s brakes. He was planning on replacing his rotors and wheel bearings as well, he had the steering knuckles off and didn’t know what to do next, and the Hobby Shop was going to close in an hour and he needed his car by then. The instructors didn’t know how to do them either. I helped him and together we finished just in the nick of time. Note that the above is an attempt to get back some of my ego.
Check the fitting that screws into the intake manifold that the brake booster hose attaches to. They are prone to becoming plugged/restricted on high mileage cars. BTW it will show normal vacuum readings on a gauge, but will not supply enough volume to operate the booster correctly if it is restricted.
Thanks, I’ll check that too.
This is getting desperate, you seem to have covered everything.
When you bled the brakes, assuming you followed the correct bleed sequence - did you adjust the rears shoes up to max ie to lock the wheel ? May sound insignificant but I’ve come across a couple of problems before where instead of the air being expelled from the rear cylinders during bleeding it escapes into the end of the cylinder and pushes the piston, a very small amount of air but it caused exactly these problems.
Good luck.
No I didn’t. Would setting the parking brake work as good? I can’t remember if I set it or not, but I don’t think I did because I pulled the drums each time looking for anything that I might have overlooked earlier.
Nope, setting the parking brake doesn’t work.
You max adjust the shoes so that the brake cylinders expand to that adjustment and then have no further movement since the shoes will not retract and recompress the cylinder pistons.
The rear brake mechanical system is therefore static.
Once you have completed bleeding the system, you can back off the shoes again.
The problem I’ve heard about seems to be the air shuttling around inside the cylinder with being expelled, instead of the pressure expelling the air, the air compresses but uses the piston as an escapement. It’s rare but I’ve heard it occur a few times.
Since you’ve pressure bled, I’d guess the bleed nipples themselves are also okay.
BTW - Do you have brake pipe bending & flaring tools at hand ?
Two thoughts:
- You might have a bad hydraulic brake hose from the replacements. With eye and hand examine each hose assy. as an assistant steps on the pedal hard. Look mostly at the single one to the rear.
- Poor function in rear drum self adjusters could be responsible for the symptoms of long pedal throw and low braking force.
There are two to the rear, one for each side. It’s an X brake system developed by Saab. That is the LF and RR are on one circuit and the RF and LR are on the other. I did check for bulging while my son stood on the brake pedal.
I’ve had recommendations about going to braided SS lines but haven’t seen any for this car. I haven’t looked seriously yet though and I’m not thoroughly convinced they are worth the money. I’ve heard they run in the neighborhood of $140. Not to sound like a cheapskate, I’d do it in a heartbeat if I thought it would have a measurable affect, but the regular lines have been in use for a long time and as long as they are change every ten years or so, they don’t usually cause problems.
I don’t have flaring tools and I’m not sure that I can adjust the brakes like you say, I don’t see a hole in the backing plate like every other drum brake I’ve worked on. The FSM shows adjusting them with the drum off with a brake shoe measuring tool. It looks like a cheap caliper, one side measures the ID of the drum, flip it over and measure the OD of the installed brake shoes.
There’s not much room to see if there is a hole, the wheel cylinder is just above the axle tube and the adjuster is between them. If I can’t adjust them externally, then I will adjust them as far as I can and still get the drum back on and then set the parking brake. That should prevent any movement within the wheel cylinder.
To clear something up, the rear brakes are adjusted correctly, the self adjusters work. The shoes make contact with the drum, it’s just that they don’t seem to have enough friction. With the parking brake set, it is possible to move the car, takes more force but it will work. If you pull the parking brake handle while rolling, you can feel it slow down the car, but I’ve had parking brakes that work a whole lot better. According to the FSM, everything is to spec and functioning, its just not working like it used to or as I think it should.
Damn !
If you can’t lock the shoes up, then there isn’t much you can do to check this.
A desperate measure but you could try disconnecting the rear brakes hydraulic circuit, make up a short isolator circuit to replace the rear brake circuit.
Don’t drive on the street with this, it’s just to prove that the problem lies in the rear brake system.
If the problem is still there, at least you know that the rear brakes are a red herring and the problem lies elsewhere.
Do you suppose that I could put a C clamp on the wheel cylinders and bleed it that way?
You could certainly try, but it may be a lot of work for no result.
One other thing, is the footbrake return spring operating correctly and returning the pedal to the correct position ? I can’t help but think that the problem is originating in the MS, though I know you have replaced it several times and state that the push rods were adjusted correctly.
Was my last post censored?
You might find a remote, little travelled gravel road and from a speed of 5+/- mph slam on the brakes and when remain just where it comes to a halt. Get out and look at the wheels to see if gravel is pushed ahead of all 4 tires.
If you “stand on 'em,” can you lock all 4 of the brakes at say 30 mph? Will ANY of the wheels lock?