Repair-It

Adam wrote:Good point. I had to undo the master cylinder yesterday in order to remove the proportioning valve. I don't think it sat completely flat...

I don't know for a fact that it should but it seems like it should...

If that's the case, I could modify the pushrod. Stupid aftermarket junk. I suppose just cracking the bleeders and letting the pressure out might "fix" it enough. I should see what the brake code is.

That's what I thought. But when the return ports are not exposed because of the position of the master piston, it will keep happening as the fluid warms, expands and has nowhere to go.

Another thought: I have a whole 4-wheel disc rear end. I could do a rear disc conversion and go back to the bolt upgrade kit. With dual 3/16" lines, that is more fluid delivery area than a single 1/4" line split between the two sides so fluid delivery wouldn't be an issue.

The hard part I thought was maintaining ABS because your axle flange does not accept the disc backing plates. Because you have ABS reluctors at the end of each axle, not just a pinion reluctor. I could be wrong but I did not think it was a bolt-on conversion.

kevm14 wrote:I have pictures somewhere of my original 93 pushrod and probably the one from the 95 9C1.

Found them. Date tagged December 2003. You can see their length is not the same.

kevm14 wrote: The hard part I thought was maintaining ABS because your axle flange does not accept the disc backing plates. Because you have ABS reluctors at the end of each axle, not just a pinion reluctor. I could be wrong but I did not think it was a bolt-on conversion.

http://www.cadillacforums.com/forums/rw ... rsion.html

2 things that you should know--the ABS sensor is repositioned from its present location at the bottom side of the drum brake backing plate. For clearance, a small amount of grinding on the axle housing flange--where the backing plate is bolted on--will be required. Also, it will requre that the 2 rear ABS sensor/cable assemblies get swapped from side to side to maintain proper sensor orientation to the tone ring on each axle shaft.

Some modifications required, apparently.

I suppose its possible that the replacement master cylinder I ordered wasn't exactly right. I have not done anything to the booster on the FW. I do have the booster off the Caprice for reference/parts.

This is something that happened to me when I switched boosters. I switched master cylinders without issue. But maybe that was just luck and there are at least two different piston "heights."

I would have to assume that I wouldn't have had an issue if I used the master from the car I got the booster from.

Looks like I bought that M/C back in July of 2013. It was a "AUTOSPECIALTY/KELSEY-HAYES" brand. They still carry that brand, but it is on closeout for $22.57 while the others are all much more money.

I'm going to get that bleeder kit and evaluate the master cylinder's ability to suck fluid back up.

Another thing I could try is swapping the Caprice master cylinder onto the Fleetwood. The part listing is different between the 4 wheel disc Caprice part and the Fleedwood part, but they might be similar enough. I would have to swap the reservoirs as the FW has the extra fluid return line from the ABS unit.

I used the bleed kit to verify the master does indeed work. I'm pretty sure whatever the alignment of the pushrod doesn't matter in this case, because: there is no fluid flow out of the rear cylinders.

I removed the bleeder entirely from both sides and no fluid came out when pedal force was applied. Not even a drip (like I've seen when trying to bleed with the shuttle switch engaged).

So there is either an obstruction or the ABS unit has failed in some strange way. I've applied penetrating oil to the lines on the ABS unit so I can verify fluid flow out of it (meaning the obstruction is somewhere in the lines/hoses or the ABS unit itself. I guess this proportioning valve could be a problem too, but I'm pretty sure fluid came out of both sides of it during the installation yesterday. I have a spare, so I could just install that again...

Going to pull brake codes and see what the ABS pump bleeding procedure is.

Looks like part of the problem is my poor reassembly of the spring/valve/seal inside the proportioning valve combined with the seal being swollen to a too-large size and it consequently looking mangled on the way out. Swapping the parts in from the FW's original proportioning valve feels much better on reassembly and fluid now comes out of the bottom of the valve. Now to see if the fluid can make it to the rear of the car...