240 Brake warning light after rebuilding front brakes

karlis m · 11-08-2011, 04:17 AM

Hi!
This indicator light on instrument cluster makes me worried. It came on after I repaired my brakes

I had bad front brake calipers. Took them off, put in new cylinders and rubbers, changed brake lines. Bleeded whole system fine, works perfectly. No issues with brake booster.
But after it, this light came on and it won't go away. Brake fluid level is fine, does not drop, no leaks in the system after 500 km.

How can I 'delete the mistake'? Is there possibility that I have damaged some wire? I looked for one, but did not find anyone coming out from the master cylinder of brake fluid cointainer.

Could someone describe the situations what may cause the appearance of this warning light?

cleanflametrap · 11-08-2011, 08:07 AM

Quote:

Originally Posted by karlis m

Hi!
This indicator light on instrument cluster makes me worried. It came on after I repaired my brakes

I had bad front brake calipers. Took them off, put in new cylinders and rubbers, changed brake lines. Bleeded whole system fine, works perfectly. No issues with brake booster.
But after it, this light came on and it won't go away. Brake fluid level is fine, does not drop, no leaks in the system after 500 km.

How can I 'delete the mistake'? Is there possibility that I have damaged some wire? I looked for one, but did not find anyone coming out from the master cylinder of brake fluid cointainer.

Could someone describe the situations what may cause the appearance of this warning light?

The image threw me. Doesn't appear on any of my 240's. Given you don't find any wiring at the master, I would deduce your 240 is pre-ABS years, which for the US would be up until 1990. The 91 and later cars use a float switch in the master rez, even for those 91's without the ABS which was optioned that year. These earlier cars derived the brake warning light from a pressure balance switch in the brake junction box, sometimes referred to as the "octopus." The problems with them are usually caused by rust and contaminated brake fluid; leakage past the o-rings. Or, of course, a real problem in the dual-diagonal brake hydraulics resulting in unbalanced pressure.

John2x240 · 11-08-2011, 04:11 PM

Try disconnecting the warning light electric lead on the cap of the junction block and backing it off a few turns, enough so that the pistons in the junction box will centre themselves and the warning light should go out. After this, tighten up the cap and re-connect the lead, then test the brakes to make sure the light is out.

MCPeach · 11-09-2011, 01:34 AM

Nice John, I can't wait to try it out. Great to avoid major messyness.

karlis m · 11-09-2011, 05:36 AM

Thank you, sounds pretty easy. I will try this, then write back of was it enough to solve my problem.
and yes my volvo is european 1990 model, registered in 1989 and it does not have ABS

John2x240 · 11-09-2011, 04:08 PM

I learned a long time ago with my 140s to disconnect the warning light wire and back off the cap before bleeding the brakes. This way the pressure in the "octopus" will even out and not set the warning light when you've finished bleeding and tighten the cap

cleanflametrap · 11-11-2011, 07:38 PM

Quote:

Originally Posted by John2x240

I learned a long time ago with my 140s to disconnect the warning light wire and back off the cap before bleeding the brakes. This way the pressure in the "octopus" will even out and not set the warning light when you've finished bleeding and tighten the cap

My puny collection of Volvo trivia has led me to believe the octopus in a 140 is a different species from that in a 240. The 140's requires resetting, via that procedure to pull the switch back from the shuttle, where the 240's is supposed to be self resetting (has a centering spring). However I would believe someone if they said the switch pressure was enough to keep the shuttle from moving after a brake stomp. The divot shown in this photo implies there is some appreciable pressure offered by that switch pin, and maybe just enough friction if it gets hung on the metallic edge of the shuttle.

John2x240 · 11-12-2011, 12:31 AM

Art, I didn't know about self-resetting. When I got the '88 244 I took it to a tech that was supposed to be able to fix older Volvos for a full check-up including bleeding the brakes. When I got the car back the brake light was on, and when I asked him about it he said it must be a wiring issue as the brakes worked fine, and to just mask over the light or pull the connector on the balance valve. When I got it home after a few hard stops the brakes were fine, as he said. I found the balance valve was in a different place than my 140s, but it looked pretty much the same as the one in my green book for one of the old 140s I'd had back in the '80s, so I loosened off the cap just as I used to do and the warning light went out and didn't come back. About six months later I had to change the front calipers on the '89 car and with the calipers changed I bled the brakes according to my then new Bentley book and the warning light was on, so I loosened off the cap as I did with the '88 car and the warning light went out, so I just assumed that this was a normal step as it was with my 140s. So now, if the warning light on the 240s is supposed to be self-resetting, maybe there's something wrong with the balance valves on my cars?

cleanflametrap · 11-12-2011, 06:33 AM

I think your procedure is a good one regardless of the design. The part I like best is you don't completely remove the switch (like I do to clean the rusty crud out of it) so you don't encounter the challenge of trying to re-thread the nylon body into the rust-swollen casting. Whatever makes the light go out - and stay out - without defeating the circuit, is a good fix in my book. I surely don't like the answer you got from your "tech."

John2x240 · 11-12-2011, 03:52 PM

Quote:

Originally Posted by cleanflametrap

... I surely don't like the answer you got from your "tech."

I didn't either; I never went back to him.

11-08-2011, 04:17 AM	#1
karlis m Board Member Join Date: Mar 2011 Location: Europe, Latvia, Riga	Brake warning light after rebuilding front brakes Hi! This indicator light on instrument cluster makes me worried. It came on after I repaired my brakes I had bad front brake calipers. Took them off, put in new cylinders and rubbers, changed brake lines. Bleeded whole system fine, works perfectly. No issues with brake booster. But after it, this light came on and it won't go away. Brake fluid level is fine, does not drop, no leaks in the system after 500 km. How can I 'delete the mistake'? Is there possibility that I have damaged some wire? I looked for one, but did not find anyone coming out from the master cylinder of brake fluid cointainer. Could someone describe the situations what may cause the appearance of this warning light? Last edited by karlis m; 11-08-2011 at 05:12 AM..

11-08-2011, 04:11 PM	#3
John2x240 Board Member Join Date: Oct 2010 Location: Sarsfield,ON	Try disconnecting the warning light electric lead on the cap of the junction block and backing it off a few turns, enough so that the pistons in the junction box will centre themselves and the warning light should go out. After this, tighten up the cap and re-connect the lead, then test the brakes to make sure the light is out. __________________ '88 Volvo 240 auto (now a parts car), '89 Volvo 240 5 spd. (now a daily driver), '92 245 5 spd. (new my car), '80 Holiday Rambler/Ford E350 (tow vehicle and track crash pad), '95 GMC K2500 (local hauler/back-up tow vehicle), '83 Mazda RX7 (race car when I have the funds), '99 Miska 20' car hauler. The man's prayer: "I'm a man, but I can change, ... if I have to, ... I guess."

11-09-2011, 01:34 AM	#4
MCPeach Board Member Join Date: Nov 2009 Location: Winnemucca, Nevada	Nice John, I can't wait to try it out. Great to avoid major messyness. __________________ Manifest Dichotomy 4th Swede: '90 245; M47, V cam, sways, 300k.mi., very near to zero 9th Italian: '81 Fiat (Futile Italian Attempt at Technology) Spider; 250k.mi., past zero

11-09-2011, 05:36 AM	#5
karlis m Board Member Join Date: Mar 2011 Location: Europe, Latvia, Riga	Thank you, sounds pretty easy. I will try this, then write back of was it enough to solve my problem. and yes my volvo is european 1990 model, registered in 1989 and it does not have ABS

11-09-2011, 04:08 PM	#6
John2x240 Board Member Join Date: Oct 2010 Location: Sarsfield,ON	I learned a long time ago with my 140s to disconnect the warning light wire and back off the cap before bleeding the brakes. This way the pressure in the "octopus" will even out and not set the warning light when you've finished bleeding and tighten the cap

11-12-2011, 12:31 AM	#8
John2x240 Board Member Join Date: Oct 2010 Location: Sarsfield,ON	Art, I didn't know about self-resetting. When I got the '88 244 I took it to a tech that was supposed to be able to fix older Volvos for a full check-up including bleeding the brakes. When I got the car back the brake light was on, and when I asked him about it he said it must be a wiring issue as the brakes worked fine, and to just mask over the light or pull the connector on the balance valve. When I got it home after a few hard stops the brakes were fine, as he said. I found the balance valve was in a different place than my 140s, but it looked pretty much the same as the one in my green book for one of the old 140s I'd had back in the '80s, so I loosened off the cap just as I used to do and the warning light went out and didn't come back. About six months later I had to change the front calipers on the '89 car and with the calipers changed I bled the brakes according to my then new Bentley book and the warning light was on, so I loosened off the cap as I did with the '88 car and the warning light went out, so I just assumed that this was a normal step as it was with my 140s. So now, if the warning light on the 240s is supposed to be self-resetting, maybe there's something wrong with the balance valves on my cars?

11-12-2011, 06:33 AM	#9
cleanflametrap Board Member Join Date: Sep 2009 Location: near baltimore	I think your procedure is a good one regardless of the design. The part I like best is you don't completely remove the switch (like I do to clean the rusty crud out of it) so you don't encounter the challenge of trying to re-thread the nylon body into the rust-swollen casting. Whatever makes the light go out - and stay out - without defeating the circuit, is a good fix in my book. I surely don't like the answer you got from your "tech."