740 brake warning lighgt

  • Thread starter Thread starter Jim Corey
  • Start date Start date
J

Jim Corey

Replaced the pads, turned the rotors and replaced the RF caliper on my 86
740. The brake warning light sometimes glows faintly. Comes on full at
start. The faint glow goes away, and then returns. No discernable pattern.
Any thoughts?
 
Jim Corey said:
Replaced the pads, turned the rotors and replaced the RF caliper on my 86
740. The brake warning light sometimes glows faintly. Comes on full at
start. The faint glow goes away, and then returns. No discernable
pattern. Any thoughts?
Click to expand...

Probably some crud lodged in the brake failure sensor, it's not too hard to
take the plunger out and clean it up, but you'll have to bleed the brakes
afterward.
 
James Sweet said:
Probably some crud lodged in the brake failure sensor, it's not too hard
to take the plunger out and clean it up, but you'll have to bleed the
brakes afterward.
Click to expand...
I don't see an alternative. In the past I've tried to just re-center the
plunger but if the shuttle doesn't move freely there is no hope. Aren't
there o-rings to replace in the sensor? My memory is vague.

Mike
 
Michael Pardee said:
I don't see an alternative. In the past I've tried to just re-center the
plunger but if the shuttle doesn't move freely there is no hope. Aren't
there o-rings to replace in the sensor? My memory is vague.

Mike
Click to expand...

Yeah there's O-rings in there, the plunger actually consists of about 5
pieces, but I've never had to replace them.
 
Are the sensors clean not covered in metal filings are the same sensors
tight and the leads to them not frayed through ?
 
John Robertson said:
Are the sensors clean not covered in metal filings are the same sensors
tight and the leads to them not frayed through ?
Click to expand...

I don't think this is the ABS light he's referring to but the Brake Failure
light. Some clarification would be good, but I don't believe '86 had ABS.
 
Non ABS. I'll check the sensor. To save my looking it up, where in the
system is it?
 
Jim Corey said:
Non ABS. I'll check the sensor. To save my looking it up, where in the
system is it?
Click to expand...

Get under the car and you can't miss it. It's on the frame down below the
brake booster, it's a small metal block which has about 8 metal lines and a
wire going to it. There's a cap on either end and if you take those off you
can poke the plunger out.
 
Thanks. As the 740 is the WIFE'S car, I gotta get the project done. She's
had it since t was new, about 400,000 miles ago (the odo quit at 323,000 3
years ago).

Jim
 
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