Saab 900: Rear Brakes Are Hapenning

Kinja'd!!! "Urambo Tauro" (urambotauro)
02/19/2018 at 12:00 • Filed to: saab 900, project, wrenching

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The old calipers have been shipped out for core return, and the return money has already been spoken for. Stick around til the end of this post to find out why...

I had some leftover caliper paint from my !!!error: Indecipherable SUB-paragraph formatting!!! that was still good, so my brother made good use of it. The nice thing about these new (reman) calipers is that prep work is minimal.

Unfortunately, we soon realized that maybe we should have focused on the exhaust or something else first instead. If we put the brakes on now, the new rotors could accumulate some rust before we manage to get this thing on the road. So for the time being, we’re focusing on the hydraulic stuff like calipers and hoses. The new rotors will stay in the boxes, protected by a sheen of shipping oil. Once the tires are here and it’s ready to drive, we’ll clean the oil off of the rotors, and slap ’em on with the pads.

We transferred one of my clamps to the rear/center/upper brake hose, and installed the fresh rear calipers with new hoses. We also strategically applied some anti-seize to the bleeder screw threads in hopes of never ever having stuck bleeders again.

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Plywood to simulate pads and rotor to keep the piston from popping out during bleeding

Once both rear calipers were on, we cut the rear/center/upper hose behind the clamp and tended to the rust built up around where it connects to a T-fitting to feed both rear calipers. Once that was taken care of, we were going to have to work quickly to prevent fluid loss and air contamination.

This car has the main rear central hard line routed through the interior of the car, and its connection to the center brake hose takes place underneath the rear seat. (It sure is nice to wrench on a rust-free connection for a change...)

With a rag stuffed underneath the fitting to catch fluid, the old hose was disconnected and quickly replaced with the new one. We then immediately got to work on bleeding the brakes before any air had a chance to migrate up to the ABS unit. The book doesn’t give any special instructions or warnings about bleeding an ABS unit that has gotten air in it, but we were careful all the same to avoid that situation and keep it full of fluid at all times.

Due to the routing of the brake line, the LR caliper is the furthest from the master cylinder, so we started with that one first. The fluid came out a milky brown:

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Yuck

The bubbles soon stopped, but we wanted it to run clear. But after filling this cup about half a dozen times, we realized that we were going to need another quart, at least. So we decided to just focus on getting the air out for now, and move on to the RR caliper. We’ll have to do a more thorough flush later to get it to run clear.

!!! UNKNOWN CONTENT TYPE !!!

Still couldn’t get it to run clear. It’s gonna take a lot more fluid before we’ll get it clean. In the meantime, we pinched the front hoses and removed the front calipers. We were going to run the engine again to give it some exercise, but...

No start. No crank, even.

I checked the solenoid, and while it was making a nice firm CLICK, power wasn’t reaching the other side. Welp, there goes that core refund money.


DISCUSSION (4)


Kinja'd!!! CalzoneGolem > Urambo Tauro
02/19/2018 at 12:28

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You’re going to have a regular ship of Theseus by the time you’re done.


Kinja'd!!! Akio Ohtori - RIP Oppo > Urambo Tauro
02/19/2018 at 12:40

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Not sure I follow, but you couldn’t get the stater to engage? You might try throwing in a $1 interposing relay as a “hot start fix” (but also fixes non-starting due to weak voltage at the solenoid) to see if that helps. Alternatively you could jump battery voltage directly to the solenoid to see if it is a voltage problem, or a solenoid problem.


Kinja'd!!! Urambo Tauro > Akio Ohtori - RIP Oppo
02/19/2018 at 12:49

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Signal reaches the solenoid, but something’s wrong inside. It has good voltage going to the solenoid, but despite letting out a firm CLICK, it’s not getting through to the other side.

So the solenoid is bad, but we didn’t even bother jumping the terminals to test the starter motor itself. Frankly, I’m not sure I trust the starter motor to last much longer than the solenoid. Might as well just replace them both as an assembly at the same time.


Kinja'd!!! shop-teacher > Urambo Tauro
02/19/2018 at 17:12

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The hits just keep on comin’!