Last night I tried the Foster approach and clamped all the rubber brake lines with C-clamps. The pedal was high and hard. I removed the clamp from the left rear line and I still had pedal. I then removed the clamp from the right rear line and I still had pedal which means the rear brakes are fine. I then removed the C-clamp from one of the right front lines and the pedal was not as hard and went down a little, but not to the floor like before. I bled that line until I had a hard pedal again and then removed the second C-clamp from the right front and bled the caliper again until I saw no more air bubbles coming out and the pedal was hard.

I was almost home free when I went to the left front and removed one of the C-clamps. The pedal went down like it had done on the right side, so I followed the same procedure bleeding the left front caliper. While bleeding the second line, the @#$%#$ pedal sank to the floor again! Darn it....!

I clamped off all the lines again and the pedal still sank to the floor this time. I removed the brake lines from the MC and reinstalled the plastic plugs.
The pedal was no longer hard and slowly sank to the floor which means the MC seals were probably toasted while bleeding the front calipers. This is the second MC I have installed. The first was leaking fluid behind the MC into the booster. Took it back and got another one and now that one is bypassing internally because it now fails the dead head test with the plastic plugs.

So now I have another decision to make.....

1)Install a new (not rebuilt) MC, and try again.
2)Throw in the towel and let the Volvo shop finish the job.

So it would appear that there was some air in the front calipers despite pressure bleeding the system, but now the MC is toasted again, possibly from my wife pushing the pedal while we were bleeding the front calipers.

So what would you guys do from here... Go for another MC or call the tow truck and be done with it? I put the wheels back on last night just in case I decide to have it towed this morning. I'm calling Carquest to see if they sell "NEW"
MC's because the rebuilt ones are not holding up very well and appearently they are not recommended by brake repair shops.

Special thanks goes to all of you guys who have stuck with me through this and especially to Don Foster for his C-clamp recommendation that helped me quickly analyze where the problems areas were. I thought sure I had it licked until the pedal went soft again. I have to return the rental car today so I have to decide whether to make another repair attempt with a new MC or just give it up at this point.

Your thoughts and opinions would be appreciated.... what would you do?

DeWayne

So....WHAT did the shop find out?(NMI)
--
www.fidalgo.net/~brook4

They installed a brand new master cylinder (the third one!) and vacuum bled the system again. The two rebuilt master cylinders I got from Carquest were crap but the rebuilt calipers were fine. We haven't picked up the car yet because they were unable to finish it yesterday. They gave us a loaner Volvo that has 268K on the clock. The engine doesn't have much power left but it's still going.

I knew that the second MC was bad and probably could have fixed it myself but I was frustrated and out of time at that point. I tried pressure bleeding, gravity bleeding, and manual bleeding of the brake lines following the proper bleeding sequence so I don't see how I might have missed anything or screwed up.
Either these Volvo system are extremly hard to bleed properly or I was just the victim of bad circumstances using rebuilt parts and limited experience doing brake work. I don't know what the final total bill is yet, but this has turned out to be a very expensive education that I hope to aviod in the future.


DeWayne

Sure sounds like you got air in the system again, and this time including the plumbing and MC.

One possibility is that the reservoir emptied during bleeding. However, you're sure it never emptied.

Another posibility is.....      No, let me tell you what my wife did when she helped bleed the brakes.

She would pump the brakes up and hold pressure. I would crack the bleeder, and the pedal would drop. When the pedal hit bottom, she immediately released the pedal so the bleeder suuuucked air back into the caliper.

Over and over this happened -- I could not change her evil ways. We went through this drill about ten times until I fired her from the job.

No amount of retraining would help -- her brain was hard-wired to release the pedal when it hit the floor. (This is just like her pumping the gas pedal in her 740 to "prime" it for a cold start. No persuasion can change the habit, even though we've owned FI Volvos since '73. It's hopeless, I tell you, hopeless...)

So I have a stick with a groove in the top (to wedge under the steering wheel) and the right length to hold down the brake pedal. I pump-pump-pump and then wedge the stick and then open the bleeder.....

...and wife's outta the picture, fixing lunch or doing something useful.
--
Don Foster (near Cape Cod, MA)

It appears that you are very clever and knowledgeable on the use of the pedal during bleeding procedures but the wifey has a problem in this area. I see a possible soultion. You pump the pedal and let her manipulate the 10MM on the bleeder screws.

"...and let her manipulate the 10MM on the bleeder screws..."

Whadda ya, nuts??? She'd have every bleeder broken in under a second. You should see how she can bleed, rounce, ruin, destroy, decimate, eviscerate, annihilate, incinerate a harmless, helpless credit card. Particularly if it's my credit card. And she does it without a wrench.

No, it's better that she stir the soup and I bleed the brakes.
--
Don Foster (near Cape Cod, MA)

When my '84 240's MC finally died at about 250k miles, I spent the big bucks on a brand-spankin-new genuine OEM Ate master cylinder. Cost about $100 at the local hi-dollar import parts store, but RPR has them on their website for $69.99: http://www.rprusa.com/frset3.htm

With the new MC I just threw it on, bled it quick, and it was good to go. Hasn't leaked a drop, works just fine.


I've screwed with brakes enough over the years that I've learned to find the best quality parts I can afford. If you're contemplating having a Volvo shop deal with the problem, you can probably afford the OEM parts. A shop is going to put on decent parts, charge you almost double for them, and charge a bunch of labor as well. If you buy a new MC and you still can't get it to bleed right, the shop will at least have new parts to work with. And they come with guarantees.

Mike

THANK YOU for being so perserverant (sp?).

So the pedal did go hard with the "Foster Tube Clamp Method" (FTCM). Was it instantly hard? (you know like when you were a teenager) or did it take a few pumps? (don't GO there). Serious question.

I shotgun think they have some bad MC's in stock.....that were hard with the FTCM, but wouldn't move enough fluid to bleed all air. The little work you did make the thing do, killed it.

There is still the remote possibility that your front piston seals on your (rebuilt?) calipers are iffy as well.
--
www.fidalgo.net/~brook4

When I clamped off the brake lines, the pedal was very hard which was a good sign. I was especially pleased when I removed the rear clamps and I still had a solid pedal at that piont. The front calipers did have some air in them which I bled out up until the final brake line where the MC went south and I lost the pedal again.

After a few phone calls and weighing my options, I decided to have the car towed to the repair shop to finish the job because my wife needs the car back. When I looked at how much of my time and effort was being spent trying to fix the car plus the added expense of the rental car, parts & brake fluid, plus time and gas running to the parts store, it then became more cost effective to have it towed to the repair shop.

If we had another car for my wife to drive and I had more time to spend working on the Volvo, I would have stayed with it until the end, but I was forced to draw the line and cut my losses on this one. It's embarrassing to have a car towed from you own garage, especially when the neighbors know you've been working on it but I felt that I had reached the drop dead point and needed the car fixed.

When I get the car back, I'll let you know what they did to fix it.

DeWayne

If you bought a rebuilt caliper and it is defective at least get your money back. Have you tried pressure testing your original MC or did you already trade it in? You could get a new one but it is really going to set you back. Do you have any junkyards in your area? Get a MC of a junker that still has a sealed system. Volvo MCs are really dependable. I am on my 4th 240 (none newer then 12 years old) and I have rebuilt one MC on all of those cars. Chances are one from the junkyard will work fine. You might also consider rebuilding your original MC if you still have it, at least you know where it has been.

By any chance, did you allow the resevoir(s) to run low while bleeding, which would have introduced more air into the system?

I've also seen problems with replacement MC's, where the piston depth is slightly different and therefore the rod coming out of the booster has to be re-adjusted. If the rod is pushing much against the piston when you bolted the MC to the booster, it may not be allowing the piston to retract far enough to get an adequate charge of fluid in front of it. Or, in a more sever case, it may be pushing the piston far enough forward that when your wife buried the pedal to the floor, it damaged the seal on the front piston.

I never allowed the reservoir to run dry or even get down to the minimum level.
My wife had her other foot under the pedal so it would not go totaly down to the floor. The MC bolted up to the booster with no problems. I think the rebuilt MC's are crap. I called Carquest and they do sell new ones at a higher price.
They didn't question me when I told them that I had gotten two rebuilts that went bad. He said just to bring it back, so I suspect that it's nothing new to them. I'm going to attempt one final MC swap since I came so close to getting it fixed last night. A new MC and a little more bleeding the front calipers will hopefully restore the brakes.


DeWayne