PLease tell me if you can, what would cause this light to come on. I am on my 3rd master cyl. in 6 months (car came with a bad one, the first replacement leaked...this is another replacement in use. Is there something else? I can see no leaks at the wheels. It is an intermitant problem.

My front junction block was leaking, its by the right control arm.

I had this happen after replacing the MC on my old '83 240. I had to go through the bleeding procedure again to get the light off. The bleeding procedure for a 240 is fairly complicated since there are three bleeding valves on each front caliper and one on each rear caliper. They must be bled in a certain sequence, not just one wheel at a time. When I did a brake fluid flush on my '86 240, I used an Eezibleed unit which uses air pressure from a tire to push the fluid through the system. Worked great!

Another possibility is a leaking junction block. It's never happened to me but a Volvo mechanic once told me that some of the junction block castings had a thin spot right next to one of the mounting bolts and leaks can develop there. I'd look closely at the block to see if it is leaking.

Jim,

I have only found two bleeder valves on my 91 240. i have girling calipers. You mentioned a sequence to bleed the lines, do you know what it is?

Keep looking. On the front calipers there are: 2-lower chamber bleeders on the middle of the caliper alongside the pads, inside and outside. Each front caliper also has a top chamber bleeder on the top of the caliper. Note: if you have ABS brakes, the calipers may be different, I haven't seen the Volvo ABS calipers.

The bleeding sequence is :

1. Left rear

2. Left front top chamber (single bleeder, top)

3. Right front top chamber (single bleeder, top)

4. Right rear

5. Right front - lower chambers ( two bleeders)

6. Left front - lower chambers ( two bleeders)

If you have ABS brakes, the sequence is:

1. Left rear

2. Right rear

3. Left front

4. Right front

This information comes from the Bentley manual. It has been highly recommended on the Brickboard and I get lots of use out of mine. I used its instructions to replace my 240's ball joints and top strut mounts today. It all went pretty well considering it's my first time doing these and I'm on the bottom of the learning curve. Good luck on finding yoyr problem.

I've got a rude thing to say about that Brake Failure Light!!!

I had two worthy mechanics work on my brakes and they both said if the Brakes are good (4 new rotors and two new calipers in my case) and the Brake Pedal has strong pressure.... and new fluid loss or leaks,,,, that the extra effort to get the light to turn off isn't worth it:

quote the "Swedish Pit" mechanic: "You don't want to open a can of worms with the master cylinder." They said tape over the light and ignore it as my brakes are working fine (after a good deal of work) ... unless i wanted to spend even more bucks (already about $800 for getting my old brakes back to perfection ...except that pesty light!!....

I am not totally satisfied. But I trust my brakes. You may have to compromise. Perhaps the better mechanic, who did the rear brakes but didn't finish the front, he said, that he'd have to bleed the lines three times and perhaps replace yet another caliper before he'd get the line to work. Both shops are more concerned with safty, than appearance and don't consider the light to be the valid indicator of worthiness, but only actual inspection by a mechanic (in our state, yearly inspections of brakes by mechanics are required...)

Thus the compromise: either have a qualified mechanic check your brakes, or trust the work you've done and maybe consider disengaging the light (if a mechanic says your brakes are fine, most cars don't have these lights anyway)... but probably don't just replace masters. You're probably wasting money. It could be "imbalanced" bleeding of calipers and lines are effecting "pressure" indicator.... (as suggested by the former mechanic who did my back brakes (but not a Volvo specialist... and I am a little surprized that the Volvo specialist didn't think the light was worth the hassle!!)

Gromit -

Jon's post alluded to it, but here's the process that turns on that light.

The junction block has the warning switch in it. The block is at the bottom of the two lines from the MC. They leak with age. The out-bound lines to one circuit are all on the same end of the block. In the middle, between the out-bound lines, is a piston with either a bump or a groove in the center. The switch bar rides in the groove/on the bump.

When the pressure in the two circuits is not equal, the piston moves to the low side, the switch bar moves and the light turns on.

I have "fed" a leaky junction block for months by keeping the MC topped up daily. When I goofed and the light came on, topping up and applying lots of pressure re-set the switch and shut off the light.

So your problem is one which causes unequal pressure in the circuits. It is unusual for the MC to do that, but not impossible. More likely is air in one circuit and not the other, or a leaky junction block. Look down at the block, the leak is usually around the piston seal and escapes around the wire connection. Or look just inside the LF tire. It doesn't take a lot of missing fluid to trigger the switch.

Have you been checking the MC reservoir daily? Loosing fluid?

Is this the car you carried the tool box on the ferry to go pick up?

Good Luck, and you can ignore the disclosure below, I know you don't need it.

Bob

:>)

Thanks all, and Bob, yup, it's one and the same. The M.C. was bad when I got it, I replaced it and then replaced it again. I will check the junction box and switch when the rain stops long enough. It is not loosing a significant amount of fluid. maybe a few ml's since i did the job in August. I allowed that for a bit of air in the system.

I drove the car to Qualicum Bay and back today with no problems, but since my employment status is unresolved, I am considering selling the beige bomb, and getting another fix-up car. I have done a lot of work on it, and it looks and runs very well, though the idle is high when it's warm. (I suspect a timing belt issue as i noticed this AFTER changing it for a new belt)

I picked up some hubcaps for it at the local Volvo wrecker and the sales clerk remarked that they sell cars like mine for around $4000.

Not bad considering I've spent about $1300 including body work, M.C. Water Pump, belts and new front seats!

We'll see.

Thanks all, and Bob, yup, it's one and the same. The M.C. was bad when I got it, I replaced it and then replaced it again. I will check the junction box and switch when the rain stops long enough. It is not loosing a significant amount of fluid. maybe a few ml's since i did the job in August. I allowed that for a bit of air in the system.

I drove the car to Qualicum Bay and back today with no problem

Check the junction box behind the left front wheel. I had my car in to a volvo only shop 2 months ago for injection work...my mechanic noted a leak at the junction box. I had not noted any problems with the brakes in the 4 months since I got the car, though on that day on the way to the shop they did fade considerably after some downhill heavy braking.

Anyway, he said the box is leaking from the hole through which it bolts to its bracket. I found this hard to understand but he said he's seen it before on a number of older cars. Mine's an '81 244. Replacement is around $70.

Unless this is a RARE case of an over sensitive / sticky switch you very likely have another bad master cylinder.

IF the system was properly bled when the new cylinder was installed and IF you are sure there are no leaks.

IF you have any doubt about the "Bleeding" have it done somewhere else.

Good luck

Thanks Jon, I bench bled it and it has been working fine for about 2 months. I had the brakes inspected around the same time and they were fine. I will crawl under and check myself soon, maybe take it to a brake shop. Given the quality of the last brake master I replaced, It wouldn't be too shocking if this one way hooped too. I guess I'll get the genuine Volvo one this time. (never be cheap with brakes or steering!)

Gromit, you said you bench bled it, (I assume you mean the master cylinder.) what about the rest of the system???

I can't say that I never would "just bleed the master cylinder", but I never have.

The switch as I understand it is a pressure differential device and can be tripped by the compressing of air on one side, this is why I am so adamant about a complete bleeding.

Some of these switches must be manually reset, BUT I do not know about the specifics on the one used on your Volvo.

Good luck...

PS, Please if you need a shop, do not go to MIDA__, I hate to see people ripped off.

Get one from your actual brake manufacturer if you can (either Girling or ATE), not volvo. It's the same (Volvo just oders them from the manufacturer and then marks them up)but you eliminate the volvo middle-man.

-Kenny

If the inside of the cylinder is not scratched you can just rebuild it. Its not hard to do and the kit is relatively cheap. I did it on my 75 and the cylinder outlasted the car. It doesn't take long to do. Most of the time is getting the cylinder out of the car and you will be doing that anyway.