Brake master cylinder and cruise control?

[nelstomlinson]

My '89 F350 has cruise control, and a bad master cylinder. Most of the master cylinders I can find online either say ``no cruise control,'' or don't mention cruise control at all.

So, what is the difference between a cruise control master cylinder and a non-cruise control version? Will they interchange? I absolutely need to get this thing running, but I don't absolutely need cruise control.

The truck is '89 7.3L, SRW, manual transmission.

 

[79jasper]

Just the sensor port. Technically you can jumper it.
I forget the changeover year when they went to different fittings.

Sent from my SM-G892A using Tapatalk

 

[mblaney]

+1 the one for cruise has a threaded port in the end for pressure switch o cancel cruise when you brake.

 

[mblaney]

You must be registered for see images attach

 

[nelstomlinson]

Thanks for the photo! The current defective master cylinder doesn't have that threaded port in the end, and I don't see the pressure switch or the connector either. So, I have ordered a not-for-cruise cylinder that should be here tomorrow, and I'll deal with getting the cruise control working some other time.

I suppose I could use a solenoid with its coil powered by the brake light to provide the dry contact to plug that connector into, if I find that connector.

 

[Macrobb]

My '88 uses the brake light circuit to kill the cruise, as well as a mechanical vacuum dump valve attached to the pedal.

 

[DrCharles]

I suppose I could use a solenoid with its coil powered by the brake light to provide the dry contact to plug that connector into, if I find that connector.

That's what I'd do (use a relay, like one of the common "ice cubes" for a couple of bucks). Or if you wanted originality, plumb a tee into the brake line and screw the pressure switch into it...

 

[nelstomlinson]

Mcrobb, it may be that my '89 operates the same way as your '88. Neither the old cylinder nor the new have an outlet for cruise control, and the cruise control works. I have the new cylinder in, and my front brakes work, too!

 

[papadiesel]

89 has a vacuum dump at the brake pedal, that one usually is 92 on up, 91 might be the crossover year cause I have seen vacuum dumps through 91 in f250 diesels