my brake failure octopus has a leak that is not coming from one of the brake lines. however, the idiot light remains on all the time. the brakes were spongy and i have replaced the master cylinder and they are better, but not 100%. i think i need to bleed the system but first i want to tackle the octopus problem. what do i need to replace to stop potential leaks coming from this contraption (o-rings etc)?

thanks,
chez

If you are going to open any brake lines, don't bother trying to seal the MC to stop the drips. Here is a better way —

You can absolutely Stop Brake Fluid Loss from any and all open lines by blocking the brake pedal depressed about an inch or so. Disconnect the battery to keep brake lights off.

I've been using this method on '80s 240s (non-ABS) for several years now—after learning it from an independent Volvo specialist. I made up a wooden prop that hooks to the bottom edge of the pedal and bears against the 240 seat adjuster bar. It's handy for checking brake lights too.




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Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

my brakes still don't work well.

1) refitted a mc following bench bleeding all the air out of it.
2) bleed of entire system
3) check caliper operation, brakes stop appropriate wheel spinning
4) noticed some brake fluid 95% sure the fluid is coming from the 'octopus' where there is a seal for the electrical connector

don't know what else to check...could it be the booster? the pedal drops on ignition and i cannot hear any vacuum leaks but i am still unsure.

help, what to do next before submitting the brick to the workshop.

thanks,
chez

Suggest cleaning the octopus area thoroughly with Brake Cleaner, to be 100% sure the leak is there. If it's leaking fom the warning switch, the O-rings are probably shot (see picture below). Fluid should never reach the switch plunger otherwise.

Contrary to other posts, I have successfully rebuilt two of these by installing new O-rings. Getting it free is the hard part. To rebuild or not depends on your time, skills, and finances.

The picture is from the Brickboard Gallery, courtesy of Randy Starkie.
--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

lucid,

i checked this picture out and i have already put the octopus back on the car. to my dismay i think i have placed the o-ring inside the gold ring on either side. looks like i am going to have to pull the thing again doesn't it. not for a while though as i am sick of getting covered in brake fluid. i remember you writing your trick using a piece of wood to chock the pedal a little bit and limited brake fluid loss would occur. i couldn't get this to work for me. what do you think...is it worth removing to move the o-ring to the other side or not...????

thanks,
chez

to my dismay i think i have placed the o-ring inside the gold ring on either side. looks like i am going to have to pull the thing again doesn't it.

Afraid I don't recall the exact 0-ring placement (on outer ends vs inner grooves). It's been years since I did one. The picture suggests they just go on the ends, but I can't really say for sure. I suggest you take your old one apart and see where they are on that one.

i remember you writing your trick using a piece of wood to chock the pedal a little bit and limited brake fluid loss would occur. i couldn't get this to work for me.

Lots of posters have thanked me for that tip, so it should work for you too. Maybe the pedal wasn't pushed far enough? Try for 1.5 inches, or a little more (I don't think you can really go too far).

--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

hi,

i think you are right. there is fluid coming through the switch. and since this is not meant to withstand brakeline presure i agree that the o-rings are ruined. however, after speaking to my mechanic and reading the boards both agree that a complete new octopus is needed. the haynes manual even says this too. i would be up to rebuilding one as the part costs $200 AUD but i get concerned about messing around with important stuff like brakes. i would like to know the o-rings sizes and other parts you needed for your rebuild please?

thanks,
chez

Sorry, but I don't have any details on the o-rings, as it's been several years since I did the replacements. I think I went with whatever measured slightly larger than the worn originals.

I would use new copper crush washers and a new switch/seal too, even though the plastic switch isn't the "weak link" that someone mentioned. (In a good block, it never sees any pressure, and is not meant to.) But I do think that worn switch internals can lead to a false warning light.

IMO, the biggest problem is getting it free without damaging lines and causing further grief. You might just cut one free in the breaker's yard, and work it over while giving your fittings a good long soak before going at it.

P.S. "but i get concerned about messing around with important stuff like brakes" Two simple o-rings in a part that doesn't even move in normal day-to-day operation? I don't understand what all the dire warnings are about. My guess is that they've never tried it. More complex brake parts are routinely rebuilt.
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Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

i tend to agree with you. i think $200 for a part that is reeally just a switch is ridiculous. i plan to go and pull a few from the breaker yard and see if i can find a good one. hopefully i find a decent one and i will just pop it on.

thanks for your help.

oh, if you have seen my post on the driveline clunk i would like you opinion. i get a clunk, loud and not normal like metal hitting something, when i engage D/R. i have inspected the rear suspension bushes and they lok fine and i have tested the trailing arm bushes with a crowbar under a jacked tyre. the driveshaft appears ok. what happens is the driveshaft moves a little and the axle flange "catches up" and the clunk happens. that is all i know. the fluid looked awful when i had a quick peak and i will change that today. but, i don's know how to proceed from there, even if i removed the axleshaft i doubt whether i would know what and how to replace stuff.

your opinion would be most appreciated.

thanks,
chez

Chez,

When hunting for a "good" BJB (Brake Junction Block), pull the switch first, looking for dry conditions that will indicate working seals. The plastic switch is 12mm as I recall. To get the end caps off (19mm?), I clamped it in a big vise and used an impact wrench. But a strong box-end and heavy hammer should work too.

As to the rear end clunk, I'll look for the new thread, and post a comment there.


Good luck,




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Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

I just did this job twice because of a faulty new BJB. I wouldn't recommend a used part in this situation, unless you are willing to take on a PITA job again soon.
Get under there and wire brush the area treat with PB Blaster and make sure you can break free all the lines ahead of time.
Make sure the area stays real clean and take your time.
Also to prevent a whole master from draining on you, seal off the master so no air can get in there.

Afterward bleed the system in the proper order. Not too bad of a job though.

Good luck
--
Chapster out

i have one bleed screw on rear calipers and three on front calipers. the haynes manual has a sequence that jumps all over the place. am i able to go LR RR RF LF (opening all three simultaneously on the front calipers)? referring to the 700/900 faq on brake bleeding with coke bottle full of brake fluid.

chez

I've seen that "all 3 at once" method in some very old Volvo green books (the only green books I have), but I prefer the sequence given in the Bentley and Haynes manuals.

The sequence described below bleeds each of the two separate hydraulic systems separately—whereas opening all 3 bleeders on a front caliper involves both of the two systems at the same time — which makes no sense to me.
Since the 240 has two separate hydraulic systems, the currently recommended sequence (below) bleeds each system separately.

Note that the upper two piston chambers on the front calipers form an inverted "U", with a single bleeder at the highest point. While the lower two piston chambers form an upright "U", with bleeders at the two high points.

Either A or B can be done first:

System A:
1) Left rear
2) Left front - Upper piston chambers (single bleeder, top)
3) Right front - Upper piston chambers (single bleeder, top)

System B:
4) Right rear
5) Right front - Lower piston chambers ( inner and outer bleeders, either first)
6) Left front - Lower piston chambers ( inner and outer bleeders, either first)

--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

hi,

thanks. once again you have simplified and explained this well for me.

chez

Don't attempt rebuild on the BJB, replace it. Around $65 USD. Also, don't screw around with cheap wrenches on the brake lines. Mess up one of these fittings and the job becomes a nighmare.

1) Brakes must always be properly bled to function normally... very dangerous situations can occur if not. Don't mess with the system if you can't finish the job. All or none is the best principle as applied to the brake system.

2) The purchase of an EXCELLENT line wrench, or set, can not be overstated... this was just tackled in a recent post in the last day or two.

3) Dont waste any time trying to rebuild the valve... replace it.

4) Be prepared, when replacing the valve, to f*&k up a line or two... so start the job early in the AM and set up a possible ride with a friend, or family member, to a parts store that carries what you will need.

5) PBlaster is your friend!

6) The job is simply plug & play, but at total PITA! Check the FAQ & archives!

Peace, Jon

the weak link in this cluster should never have been made of plastic, repair is not likely.a good used junction box would be an acceptable replacement, but do not remove the plastic thingy or you will be out shoping for yet another unit.use p.b.blaster, a good fitting line wrench and patientce,there is a good reason that they call the "break"lines.

You can try a rebuild kit, but the local dealer doesn't recomend it. I tried it anyway and wound up replacing the whole thing.

thanks guys. i might go and pull one from another car at a yard. but i will not attempt a rebuild from your advice.

thanks a lot,
chez