1939 ford brake lights stuck on
 

Here s what is going on Lost brakes had a bad hose third hose (one for back lines) Replaced it Also replaced master cyl. Brake lights stuck on So got new switch installed works fine, Then when car sits for a hr no pedal Checked system no leaks all good Took out new cyl replaced old one now got brakes but stop switch not working (new one that worked with other cyl) Brake lights stuck on Crack loose at master and goes out till brakes are applied What am I missing Any Ideas? (New cyl. looks to be leaking in front so I am calling that one junk out of box)

Re: 1939 ford brake lights stuck on
 

I'm not sure I'm following this. Why did you replace the master cylinder in the first place? You have a new pressure switch, did something happen to it? Is the new switch broken? Why not get another one? There are several upgrades you could do. Get a new low pressure switch or replace the pressure switch with a mechanical switch.

Re: 1939 ford brake lights stuck on
 

When I lost brakes I just decided that's what is was. Old one was in. Car for years so I replaced it when I did hose. My switch was working with new cyl Just put it back together this afternoon

Re: 1939 ford brake lights stuck on
 

I didn't read anything about you bleeding the sys after the new hose. The new cyl might have a different plunger, and the rod needs adjusted, no petal after an hour sounds like air in the system.

Re: 1939 ford brake lights stuck on
 

Check the condition of the wiring is another possibility. I had one with bad insulation with the lights stuck on. Both wires had a bare spot and were touching. Could have disturbed it when you swapped the master cylinder

Re: 1939 ford brake lights stuck on
 

Yes I bled system Matter of fact since I started with this Its been bled a bunch of times and no air at all just fluid

Re: 1939 ford brake lights stuck on
 

First thing I checked all wiring looks good

Re: 1939 ford brake lights stuck on
 

So, could you explain to me what the problems are currently? You are using the original master cylinder and both the new pressure switch and the old pressure switch are sticking on?

Re: 1939 ford brake lights stuck on
 

When I took out new cyl today its leaking in front around plunger Must been getting air and loosing pres. So that cyl is out

Re: 1939 ford brake lights stuck on
 

Ok using old master cyl Only have one new press switch same one that Was working with new cyl that is junk Now not working with old master Everything two weeks old Maybe I got to get a new switch Can I check mine with a meter or test light?

Re: 1939 ford brake lights stuck on
 

When I took out new cyl today its leaking in front around plunger Must been getting air and loosing pres. So that cyl is out

Re: 1939 ford brake lights stuck on
 

i had a similar prob once, but my brakes were builidng and maintaining pressure. i had new master then a new master rebuild kit. after i drove it a while, i'd notice the brakes dragging and the light on. a mechanic said i had the wrong relief valve in the master. he fixed it. others have told me that it prob wasn't the wrong relief valve, but the problem went away.

Re: 1939 ford brake lights stuck on
 

Is the new pressure switch stuck on or not working? It would be odd that two pressure switches would both stick on, are you sure the pressure is releasing in the system?

Re: 1939 ford brake lights stuck on
 

I drove car and brakes working fine if you release pres lights go out Step on pedal and lights stay on

Re: 1939 ford brake lights stuck on
 

What does "if you release pres lights go out" mean? Like in opening a bleed screw?
Then if you step on the pedal again the lights come on and stay on? That sounds like pressure is remaining in the line activating the switch.

Re: 1939 ford brake lights stuck on
 

Yep thats whats going on

Re: 1939 ford brake lights stuck on
 

Maybe my old master is no working 100 percent

Re: 1939 ford brake lights stuck on
 

Well guys thank you for all the help Going back to garage and mess with it for a while Maybe something will come to me Again Thanks

Re: 1939 ford brake lights stuck on
 

Sounds like it is holding pressure for sure.

Re: 1939 ford brake lights stuck on
 

Sounds like I need to get a new cyl (old one is not working right) I think that will be my next move