240 Brake junction block

Hi, new member, just wanted to post and say how useful this thread has been to me. I've been tearing my hair out trying to fix my brakes on an 89 745DL, and now I definitely know I ruined my master cylinder, and that I wasn't following an apropriate bleeding procedure.

I replaced everything due to horrible corroded I think original parts on an estate car, and to give you an idea how big a pain this brake job has been, the driver front rotor removal required complete removal of the hub, and STILL wouldn't pop off even when using a 12 ton press related to the amounr of rust jammed in there. I ended up cutting the rotor completely through and pressing off then. LF needed 4 new wneel studs an wheel bearings after that, and the other 4 have been similar level of problems

I am wondering how the OP made out? I am waiting for my master in the mail now.

OP made out .... decently.

I took the car to my friends shop and we power bled the s*** out of it - went through over a gallon of fluid, smacking brake lines, proportioning valves, junction box, calipers, etc as it went. Result: Pedal is still not solid - much better than before, but I can still push it to the floor if I push hard (not 900 lb leg press hard).

I highly doubt there is any air left in the system. Perhaps there are a few trapped bubbles in the master? I thought a power bleed would finish that off. Perhaps the master is bad again..ugh. I have just been driving with the brakes like this - they stop the car just fine, and the pedal really only goes to the floor if I push it while the car is stopped.

JB3 - sounds like you have had quite the experience with your car. What all do you have left to do

bunch of stuff to pass inspection. I desperately need to replace my lower front control arms, which are dangerously crispy, but I was using this as a DD before I thought id just whip on the brakes earlier this week.

I will start a restoration thread on it I think eventually, I don't want to derail your thread too much!

Do I need a power bleeder? this has been mentioned a couple of times here, and it seems necessary for these cars, especially after what you have been through with it. I was just gravity bleeding and using a hand vacuum pump alone.

My experience is with P-vans (think UPS size trucks), and they don't have half the failsafe design of these volvos. Was a total shock to me to see two brake lines running to those calipers, sure makes it a PITA to bleed though.

Yeah definitely start up a thread so we all have something to do at work

The Motive Power Bleeder is phenomenal - makes bleeding a breeze (if you don't have failed components ha). Definitely worth the money. Also prevents you (or your helper-wife) from destroying your master cylinder after pushing the brake pedal to the floor while manually bleeding.

mtd240 said:

Yeah definitely start up a thread so we all have something to do at work

The Motive Power Bleeder is phenomenal - makes bleeding a breeze (if you don't have failed components ha). Definitely worth the money. Also prevents you (or your helper-wife) from destroying your master cylinder after pushing the brake pedal to the floor while manually bleeding.

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think im going to pick up a motive then. I do most of my work myself, with no helpers, the GF is willing, but I hate to bother her after she works from 8am-8pm and is falling over with fatigue.

Considering the quality of some of the restoration threads ive just been reading, ill wait till i have a more interesting story to tell than, heres my car, it needs parts.

JB3 said:

think im going to pick up a motive then. I do most of my work myself, with no helpers, the GF is willing, but I hate to bother her after she works from 8am-8pm and is falling over with fatigue.

Considering the quality of some of the restoration threads ive just been reading, ill wait till i have a more interesting story to tell than, heres my car, it needs parts.

Click to expand...

Indeed - get the Motive, then.

Don't worry about living up to the restorations - start a thread! The majority of 240/740 owners are just keeping their cars alive, not fully restoring them. Plus it would be a great place to get constant advice on what to do and how to do it, without starting dozens of little threads in maintenance

mtd240 said:

Anyway, when I push down the pedal (car off, all booster vacuum diminished), and press the brake pedal, it sinks about halfway while putting out a rather loud "honking" noise, then the pedal stops solid. Is this a bad booster? Would this cause brake problems like mine?

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Just did the junction block on my 89 240, same thing is happening. Have tried jacking the car up more in the read, smacking all the lines and proportioning valves with a screwdriver handle etc, got rid of the "honking" noise but, while sitting at a light with the nose of the car downhill, the brake pedal will after a few seconds push all the way to the floor and the brake failure light comes on. Other then that, the car seems to stop just fine.

After I broke the pads in by doing 6 or so 50mph to almost stops, I can actually lock up the brakes with a hard panic brake. I'm about to pick up another quart of dot 4 and give it another go around the car. (so far have done 5 passes with the motive at 20psi, and 2 passes with friend in the car doing the pedal pushing.)

I refuse to believe it is the MC because I replaced the struts not long ago and had to bleed, didnt, pedal went all the way to the floor several times that time and still ended up with a firm push at the end.

I'm betting that doing the junction block and opening up all those lines just added some tricky bubbles I haven't gotten yet. I should also note that I sucked the MC dry with a syringe to reduce the amount of fluid that would leak out when I did the junction block.

Luckily, IF it happens to be the MC, I pulled a newish looking ATE from a JY car for $15 last week.

Anyone tried adding some pure silicone grease to the inside of the MC before bench bleeding to prevent future corrosion? Would it even be worth it?

Maybe just try gravity bleeding.No pumpimg,no injecting more air into the system.

Anyone have anything further to add to this thread? I've just started a similar thread
http://forums.turbobricks.com/showthread.php?t=266762

My pedal goes to the floor with no pressure at all, replaced mc (new cardone not rebuilt), ipd braided lines, new calipers. Power bled with motive and used up 4-5 litres worth so far and havent had any bubbles since the second bleed.
Bench bled master before install, had both lines dripping until no bubbles, then put both lines into main reservoir and then pumped until no bubbles.

Not sure what to do... almost ready to have it towed to Volvo... The brakes worked fine before all this , the only reason for starting fresh was a Kaplhenke coilover project and I knew the passenger side caliper was sticking a bit (cause of the mild rotor warp).
Figured it was a good time to redo both sides of front brakes with new and start fresh.
Used heat to remove brake fittings which were stuck, had all the nipples open and the mc cap open to prevent bursting but could i have damaged the main junction block with a tiny bit of heat? Junction block was replaced about 40k klms ago.

Havent tried the rear of the car in the air method yet, seems a bit silly to me to be honest. I cant see a Volvo dealership messing around with the rear of the car in the air. Wouldnt a motive power bleeder at 20-25psi take care of any bubbles?

OLD THREAD new question. When the "BRAKE FAILURE" light illuminates, does the plunger in the junction block also 'plug' the faulty circuit ?? In other words, Does the valve in the brake distribution block close off the circuit with low pressure? I also have no fluid getting to my left rear caliper.

No.