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Discussion Starter · #1 ·
I recently did a vacuum brake conversion on my GN and after I did it my electric fan stopped working and my torque converter is not locking-up, and my brake light is on.

The fan only comes on when I turn the car off after it is hot. And it does not come on when I turn the a/c on.

I have checked the hi and lo speed relays they are both fine, and the two red lines running to them have power, and all the fuses are fine, I thought maybe the relay 5amp fuse was blown but it was fine along with all the others. I know the fan motor works because it comes on when I turn the car off.

Any ideas would be appreciated.
help
 

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Adjust the switches that are activated by the brake pedal under the dash. When the pedal is not being depressed, the buttons on the switch should be completely pushed in.

That will fix the converter problem.

But, it has nothing to do with the fans....

You can go to my site below and add /fan.htm for help with the fan. Should have nothing to do with the fan problem (the brake conversion)

<small>[ November 24, 2003, 04:24 PM: Message edited by: Steve Wood ]</small>
 

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Ran into a similar problem, (fans) took the fan delay relay out and it cleared up...I'd say, check and see if you have a bad fan delay relay.
 

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Discussion Starter · #4 ·
Thanks Steve,

That website was very helpful. I think I have traced my problem down to the a/c high-pressure switch. Once I disconnected the switch, the fan started working fine, but I haven’t turned on the a/c yet to see if it comes on because the new switch in on order.

The torque converted locks up now, I just needed to adjust the sensor on the brake peddle, thanks again.

Now I just need to find out why the brake light goes on and off as I push the peddle in?
dunno
 

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The brake light comes on (on a vacuum brake system anyhow) due to an imbalance in the system. It is a sensor (sliding valve) inside the proportioning valve on the frame under the driver's footwell. Do you have good pedal feel?
 

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Three things to check.

1. A weak master cylinder on either the fronts or rear halves will cause this. Even if you bought a new or rebuilt cylinder, this could happen.

2. Air in the system that has not been bled out will cause it. Be sure the master cylinder was well bled and then concentrate on the lines. I prefer vacuum or gravity bleeding over pumping the pedal.

3. If the car still has the old cast iron proportioning valve, go get a brass replacement. The old cast iron valves were phased out as they tended to accumulate air over a period of time and the brakes would not stay bled.
 

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Discussion Starter · #7 ·
Put the new pressure switch in and everything works great. The strange thing is the electric fan cycles on hi speed, on and off with the compressor. I thought the fan was suppose to stay on at all times with the a/c, low speed and then hi when needed.

As for the brakes ill try bleeding the system again. I took a look at the proportion valve under the car and it looks like the original. Where should a get the brass one from?

The brake feels better then it did with the PM its not rock hard anymore, but the peddle feel soft, but it stops.
 

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Nope, the high speed comes on under two conditions-AC on, or the temp rises to some temp. I think the book says 228 but, I think the switch closes a bit over 203 in practice.

If you look at the fan part of my site, going to the diagram at the bottom, it shows that the ac switch can trigger the low fan at one ac pressure, and high fan at another higher pressure. Normally, it is always the high speed circuit.
 
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