The braking problem is on my 1985 D250 with power brakes.

When first stopping the truck after it sit's all night they like to throw you into the windshield or like they lock up and this only happens the firs 3-5 times using the brakes and then all is normal till the truck sit's say over night.

I did replace the front brake hoses but no change.

So need some ideas on what to check on.

Thanks for any help Bill

Just a guess, might be an internal booster problem. not sure if this is a correct diagnostic procedure but I would clamp the booster hose & see how it acts. Keep us posted!

my 86 D150 does this , but only when the weather is damp. I suppose it is caused by the china made brake rotors & pads. The first time it happened was a major [censored]!! Paul

My 88 Ramcharger also does this. Its usually just the first time, or two, that the brakes are hyper touchy, then good.

Its done it on two different sets of calipers, rotors, and master/booster setups, so I have no idea. I just live with it for now. I can never duplicate it for a mechanic, everything has been inspected and seems to be working within parameters.

Fits my problem to a T and I also went thru what you did and been living with this also.

Might want to try putting gauges on the calipers to see what the pressures are doing after it sits overnight. It either has to be pressure of pad related.
Might then talk to the pad supplier. I would advise having the pressure data before doing so. Another option would be to have set of pads done by an independent re-liner
keep us posted. BTW I LOVE solving problems like this

Likely surface rust that is scrubbed off after the first few stops.

I would agree if it were sitting for longer periods but Overnight???

This is from a Jeep forum and has to do with drum brakes:

The OP wrote:




Then further on he wrote this:



And this after many challenged or question his diagnosis:




Don't shoot the messenger, just what I found on the internet so it must be true or so

Now you'll come back and say your D250 has four wheel discs and I'll be and you can me

Nope only front disc's but, thanks for all the help and at my age I will just keep on driving it and let the good times roll on!!

Is it the front or rears locking up? As stated I've seen rear drum brakes exibit this issue. It was very common with Cavalier's when I worked at the Chevy dealer. We swapped rear shoes to aftermarket units . Problem solved.
Doug

I suspect the local humidity levels might play a part. Michigan isn't exactly dry.

Michigan "The Great Lakes State" what makes you say that?

Just the fronts

Ironically I had a new 88 Pontiac grand prix that had the exact opposite issue. The brakes were totally ineffective for the 1st 3- 4 stops or miles. it was a time when they were playing with composite rotors and pad materials. I had it back to the dealer several times to document the condition. The same car ATE the front Pads and Rotors with only 14K miles on them. Normal driving and the only car I've owned that didn't go 40K + on the front brakes.

I note others are posting similar issues. Can any of you see the rotor surface at all through the wheels?,
If so, you could try a kwik wipe with a CLEAN white paper towel or kleenex to see if it is wet or rusty for those thinking rust or moisture?
Or possibly to LIGHTLY ride the pedal for a 1/2 block or so?
Another question: do they all do this year round? (Humidity would be lower in the winter I would think)

Maybe add or move this post to the truck forum