Engine BRake Quit Working

[tahawus]

The Truck is a 2004 mack vision daycab. I noticed about 2 months ago it would not work all the time only once and a while. I got the oil changed and that didnt help. About a month ago it quit working entirely. I changed the relay and checked the switch but they both are ok. Any suggestions? If it is something I can fix I would like to try rather than leaving it for days at the dealership while they take there time fixing it. The truck has 24,000 miles on it. Thanks

[yoopr]

Clutch switch ok?

[tahawus]

How can I check?

[bob h]

The Truck is a 2004 mack vision daycab. I noticed about 2 months ago it would not work all the time only once and a while. I got the oil changed and that didnt help. About a month ago it quit working entirely. I changed the relay and checked the switch but they both are ok. Any suggestions? If it is something I can fix I would like to try rather than leaving it for days at the dealership while they take there time fixing it. The truck has 24,000 miles on it. Thanks

when the brake quits, does the cruise control still work?

[flood]

The Truck is a 2004 mack vision daycab. I noticed about 2 months ago it would not work all the time only once and a while. I got the oil changed and that didnt help. About a month ago it quit working entirely. I changed the relay and checked the switch but they both are ok. Any suggestions? If it is something I can fix I would like to try rather than leaving it for days at the dealership while they take there time fixing it. The truck has 24,000 miles on it. Thanks

i had that happen three years ago it was a bad wire going into the ecu took 15min to fix but it took 4.5hr to find.

bob h is right that is how i found it

[Texas88]

When my son had a problem with interment cruise, and the J brake was not working, I told him to check the switches on the clutch & brake. He Readjusted both in 10 min. and all working now. When he asked break down, they didn't have a clue how to fix it, and didn't want to have him going to Volvo dealer to fix.. They thought it was going to a major project....

[tahawus]

Cruise control does not work. The jakes worked today for 10 solid mins, then quit again. Checked the switch on the dash and it is ok and am starting to trace the wiring so far it all looks ok. :shock: Thanks for all the help so far

[bob h]

quote="tahawus"]Cruise control does not work.

interlock

The jakes worked today for 10 solid mins, then quit again. Checked the switch on the dash and it is ok and am starting to trace the wiring so far it all looks ok. :shock: Thanks for all the help so far[/quote]

check the clutch switch (by the pedal arm) for continuity, when you move the pedal forward you should hear a faint clicking sound..., that should open the circuit, and then close the circuit when you release the pedal

[yoopr]

check the clutch switch (by the pedal arm) for continuity

That's what I said a long time ago :P

[RockyMtnProDriver]

I had the same problem and it was the clutch switch. The peddle was staying down just a smidge off of the top and that was enough to make it not come on. I sorted it out by pulling up on the clutch with my foot. Once I knew that was it. I just adjusted switch a bit and it worked fine.

[Kranky]

I had the same problem and it was the clutch switch. The peddle was staying down just a smidge off of the top and that was enough to make it not come on. I sorted it out by pulling up on the clutch with my foot. Once I knew that was it. I just adjusted switch a bit and it worked fine.

More importantly, why wasn't the clutch pedal returning all the way to the top of it's travel?

A clutch pedal that's sticking is a recipe for a burned out throwout bearing, and in a worst case scenario can cause slipping and rapid destruction of the entire clutch.

Possible causes: Linkage needs lubrication, binding clutch cable, needle bearings at clutch release shaft on each side of the bellhousing are insufficiently greased, clutch pedal return spring broken or missing.

The jake brake problem may have just been the tip of the iceberg.

Instead of adjusting the switch, the issue of the clutch pedal not returning should have been addressed.

[yoopr]

I had the same problem and it was the clutch switch. The peddle was staying down just a smidge off of the top and that was enough to make it not come on. I sorted it out by pulling up on the clutch with my foot. Once I knew that was it. I just adjusted switch a bit and it worked fine.

hey Rocky-How's it goin?

[bob h]

check the clutch switch (by the pedal arm) for continuity

That's what I said a long time ago :P

actually....... what you said was; "clutch switch ok?". at that point in the thread, i would have agreed as well, but there was not yet enough info to say for sure. the brake on/off or position switch could have been bad, the electrical circuits for those switches could be the problem, the ecm might not have been recieving the engine brake request at all... these things and more could have been the problem....... BUT, now that i know the cruise doesn't work, none of those problems i just listed are possible (at least not exclusively), it's more likely to be an interlock problem

[bob h]

I had the same problem and it was the clutch switch. The peddle was staying down just a smidge off of the top and that was enough to make it not come on. I sorted it out by pulling up on the clutch with my foot. Once I knew that was it. I just adjusted switch a bit and it worked fine.

More importantly, why wasn't the clutch pedal returning all the way to the top of it's travel?

A clutch pedal that's sticking is a recipe for a burned out throwout bearing, and in a worst case scenario can cause slipping and rapid destruction of the entire clutch.

Possible causes: Linkage needs lubrication, binding clutch cable, needle bearings at clutch release shaft on each side of the bellhousing are insufficiently greased, clutch pedal return spring broken or missing.

The jake brake problem may have just been the tip of the iceberg.

Instead of adjusting the switch, the issue of the clutch pedal not returning should have been addressed.

agreed.... i was thinking of a binding pivot pin or a broken clutch return spring. if the switch "used to" work ok, why all the sudden does it need to be adjusted?

[tahawus]

Thanks for all the help. It ended up beign the switch above the clutch. It was stuck