Hey guys,

Not a newbie to volvos but my first time time on brickboard.

The car in question is my '87 244DL daily driver. About a month ago the pedal started getting slightly spongy and the master cylinder was making noises. The brakes worked fine save for some shuddering in the wheel so I put off fixing it until I had some time. Yesterday the brake failure light came on which kicked me into gear.

Autozone sold me a rebuilt master cylinder for $40. I bench bled the new one and replaced the old master in about 45 mins. The entire system was flushed about 1 year ago, so the fluid is fine. It made quite a big difference in pedal feel but the brake faliure light was still on. After some stiff braking from ~50mph to test out the brakes I noticed the car would pull to the right. Some very hard braking at lower speeds revealed the right front wheel would lock up right away while the left was still rolling.

This leads me to believe the distribution block is not doing its job dividing the pressure evenly through the two circuits. Am I on the right track here?

Any help is appreciated guys.

Thanks,

Alex

I fixed the problem. Both of the front left brake hoses had pea sized bulges. I replaced them and bled the left caliper. The local Foreign Auto Parts wanted $19.90 each for ATE brand hoses. Sure beats paying $50 each at the stealership. I know FCPGroton.com has them for $9/ea. but I needed them ASAP. The pedal feel is better than it's been in months and the car stops hard even in the wet.

I'm all set for my trip tomorrow! Thanks a ton for the help guys, much appreciated.

I would suspect you have air in the drivers side. You didn't have a pulling problem until after the MC change.

Some things to look at.
If it pulls to the right; Either the left Caliper is froze, so it wont close or possibly you have brake fluid leaking on your Passenger pads. That will cause them to be very grippy.

I think you need to bleed them again.

Pull the pads off the drivers side and Fully depress the caliper piston, when doing that, see if you get bubbles coming up in the Master. Do the same for the Passenger side. Drain a little of fluid out of the master so it doesn't overflow.



--
'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me

The car pulled noticably to the right before I swapped the master cylinder. The old master was definitely on the outs and it was time for a replacement anyway.

I removed the left front caliper and one of the pistons was definitely sticking a bit. I unstuck it and cycled it back and forth to free it up. I know I should replace the caliper or rebuild it but I'm slated to go on a roadtrip tomorrow and I need to get this thing working for at least a while.

Anyways, so I took it out for a drive and the brake failure light is still on but the shuddering is almost completely gone. The car still pulls to the right, but not as much as before, and the right wheel still locks before the left.

The brake lines on the left seem like the culprit now, since I checked everywhere and I'm absolutely positive there are no leaks.

i bought a pressure bleeder from fcp,came in one day,,,ordered before 1pm.
completely bled the front,[sticking on the fr, rght.caliper] w/ i qt.of #4 fluid, ,,after that i flushed all kinds of weird crud out&wwwwaaallla!!
no more sticking caliper,,must of flushed all the offending bits right out&saved having to replace the caliper.
oh qwai tange wah!!

i bought a pressure bleeder from fcp,came in one day,,,ordered before 1pm.
completely bled the front,[sticking on the fr, rght.caliper] w/ i qt.of #4 fluid, ,,after that i flushed all kinds of weird crud out&wwwwaaallla!!
no more sticking caliper,,must of flushed all the offending bits right out&saved having to replace the caliper.
oh qwai tange wah!!

The junction block, sometimes called distribution block, receives pressure from the two pistons in the master cylinder. It compares the pressures, and if there is an imbalance it closes the corcuit to the warning light.

I have owned several 240s in which the junction block went leaky without provocation. The problem manifests itself with a leak of brake fluid at the connection of the wiring harness to the block. The failure is of one of the 0-rings inside it.

The failure allows fluid to leak from one of the two brake circuits, allowing air to enter. This allows a pressure imbalance to occur.

When working with the MC did you notice the reservoir compartments having different levels of fluid? That will be the result of a leak in one brake circuit.

If you must drive with this condition, there is a short-term patch.

The brakes must be bled to remove air trapped between the J-block and wheel cylinders. With this leak air enters the system through the reservoir and gets into the vertical lines that go down to the block.

My method of deferring the repair was to maintain fluid level using frequent checks and having brake fluid on board. Check before leaving in the morning; check every time you park, and every time you get ready to leave. Check especially when shutting down for the night.

Brake fluid eats paint, so I carried a 12 ounce can in the engine bay propped up vertical, and a larger (lower cost per ounce) 32 counce can in the trunk, in the right side cargo compartment, propped up. The 12 ounce pours more accurately.

Air in the vertical lines will float upward into the reservoir overnight; the main effort is directed to avoiding air between the J-block and a wheel sylinder. I was successful for several months. Kept good pedal pressure and no pulling to one side.

I also modified my driving so as to avoid hard stops as much as possible. Strangely enough, I found that hard stops seem to tie in with quick starts. Dunno why, just is. Easy starts made for easy stops.

Good Luck,

Bob

:>)


PS: Replacement of the J-block is a bit labor intensive (two lines in, six lines out), so go with a dealer part to ensure getting a good one. Buy the special type flare-nut tool wrench for this job to avoid rounding off fitting corners. They are usually brass and soft metal and stuck tight. The double end 8mm + 11mm I found at a Snap-On truck (Might have been Mac Tools) while it was making a sales call at a nearby garage. Not cheap, but top professional quality.

You really do need to check all the wear items. I had very similar problems, and was puzzled as the M/C seemed OK. A number of independent 'experts' advised it was definately the M/C so I changed it. No difference.

Turned out to be the balance valves sticking, and a failing front hose.

First, it's not the distribution block. It doesn't separate right and left sides nor even front and rear, but rather the redundant triangular circuits -- each has independent control of both fronts and one of the two rears. Such an imbalance between these two circuits wouldn't make the car pull strongly to either side (one of the nice things about this unique, pre-ABS, Volvo system).

That block, by the way, is to compare the pressures in those two triangular systems -- an imbalance would set up your warning light, but I don't believe it can block either circuit so it wouldn't work right.

Anyway, I'd strongly consider the possibilities that Glen Morangie listed for you, especially a bad front brake hose (the flexible part) which are known to swell and clog, although it's awfully young to happen to any of them on an '87.

Also, seriously consider a stuck piston in one of the front calipers, too.

Anyway, to be sure, rebleed properly -- that means a positive pressure device like the Motive PowerBleeder -- make sure all the bleeders opened to evacuate air, do them in the proper order (it's best to have the car on stands all around because you have to go back and forth like "musical chairs" -- don't take any shortcuts in the steps), and don't be stingy about the amount of fluid you run through the two systems.

Good luck.

I would tend to suspect a recent change.
Air in one circuit?
I think it was Rhys that posted a bit about bleeding the MC recently.
The common failure on the block is weeping fluid at the warning switch connection.
Ken
--
White 86-245 DL, M 46, IPD bars & Wagon Overloads,Commando Bumpers,SS Belly Pan & Air Pickup,Straight-Shot EMT Chassis & Tower Braces,Scorpius Alloys,2 Belt No AC Conversion,Black POR-15 No Glare Front End

Things to cbeck are:

The front flexible hoses fail and 'balloon' under pressure, reducing the pressure to the caliper - sometimes visible as cracks near the unions.

The pressure valves under the car (a sort of two in one canister) stick and reduce pressure to the rear brakes. Vibrating the valves with a percussion device unsticks them.

Hoses, especially the rear ones, can fail internally and form a 'one way valve flap' - either causing rear calipers to bind or not operate.

The pads sometimes stick in the calipers where the body of the caliper rusts and reduces the space available.

Some reconditioned units have been found to be incorrectly matched halves, and cannot be bled successfully - there's a long thread on this somewhere, but you probably aren't worried about this if you haven't replaced any parts.

Also I think the early type of pressure switch sometimes fails and leaks.

I've never heard of a distribution block failure if any vehicle ... but that statement does not indicate plausability.

I fixed a problem of brake pull by replacing the brake hoses. Apparently the lines can degrade internally and block fluid flow. This was on a 1968 Nova so take it FWIW.
--
Norm Cook; Vancouver BC; 1989 745T 220,000KM