Son is home from school, and I have a few days to tidy up his 850.

Found that the cruise control's brake cut off switch on my son's 850 is leaking, causing the cruise to fail to hold speed. I found this after tracking down a couple splits in the vacuum line under the battery... After reading this forum it seemed simple it would be a simple fix of a vacuum line. Sure enough, found a leak, fixed it easy. Drive car. Cruise still doesn't work. Search farther down line, find another break. Gee, great design. Fix second leak, drive car, still doesn't work.

Finally rigged up a vacuum line from front of car to inside, so I could blow into the vac line while under the dash. I can hear leaking air from the cut off switch (manual calls it a "brake and clutch valve").

Actually, it appears one of the snap-in clips that hold the valve in place has broken. If I hold the valve "just right" it doesn't leak. Unfortunately, cannot do this while driving.

Any suggestions for fixing it? I'm sure those little plastic snap-in clips make it easy to put the car together but they get old and hard and break way too often. Anyway, new part is $40, so if I can spend a little time fixing it would be worthwhile.

Thank you for your help,

Terry

I know. I hate spending more than absolutely necessary on cars too but I'm guessing you'll have to go for the $40. I'd suggest zip-ties first, however.
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'98 XC '95 855 GLT '83 245 DL (245 for sale! e-mail me if your looking to buy); All over 125k miles

Don't mind spending on parts if necessary, but wanted to check first if there was a "all you need is a 10 cent o-ring" type of fix.

Resolution: Got cut out valve from dealer, snapped it in place, cruise works perfectly. Resolved issue where cruise would not hold speed, would not set at the desired speed (set at 60, it would drop to 55-ish before engaging), and accelerate function did not work at all.

Hope this helps someone else with cruise control problems and the usual vacuum-tube-under-battery fix does not work. Note: diagnosing the leaking switch is easy. Blow into vacuum line and listen for leaks. If you hear a leak, gently shift the switch and/or push in the plunger (the part the brake pedal pushes in when it is not depressed). If leaking sound stops or changes then you found it.

Options for getting to vacuum line:
- access line from battery area of car. You are probably already there since the first place to look when having cruise control problems is a bad line under the battery. Have someone blow into the line, use a pump, or (what I did) connect a line that reaches into car so you can blow into it yourself while listening for leaks.
- cut the vacuum line under the dash, lengthen the end toward the cut off switch with another small length of line. Reconnect with short length of rubber vacuum line to repair. You probably already have the rubber tubing for repairing under-battery-tray leaks.

If you have a manual transmission there is also a cut off switch for the clutch pedal.

Surprise of the day - the part was less at the dealer than it was online! Online sites show the "list price" as $39, but dealer's price was $27. That has NEVER happened before.

Thanks for the help,

Terry

If you have the part number, call www.fcpgroton.com with it. Surely they can save you some $$ on this.
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1998 S70 T5 Emarald Green Metallic, 2004 V70 2.5T Ruby Red, Previous Owner of Black '94 850 Turbo Wagon. My cars have been running so well lately they've got me worried.