Ok onto happier things, I got my '89 D-250 over the weekend and am ready to start working on it. I have a few questions that I didn't come across in the sticky.

-My wait to start and water in fuel lights do not come on when the key is in the "on" position, however they both light up in the spring loaded "start" position... Any advice on what to check first? I'm pretty sure the heater isn't working; there is no dimming of lights and the amp gauge shows no draw.

-the climate controll lever does nothing but shut the air off, or it blows air out the vents all the time. A/c wont kick on (which I realize there can be a number of different problems there, I'm not too worried now as its November). It will not switch to floor venting or defrost. It really doesn't feel like the buttons push against much of anything. Is there a big vac canister behind the dash that controls some flaps? Is it common for the button assembly to just fall apart? What should I look at?

-Brakes aren't too great. When you press the brake pedal and have it pushed say half way down, you can hear hissing from the brake booster. Is it normal to make noise like that or is the booster bad? I know it needs a master, as its leaking. Any places/brands you guys recommend? I'm not going to just throw on some autozone crap.

-When I got the truck, none of the gauges worked, but on the way home they stared reading and have been reading since then. I read through the gauge cluster refresh sticky, and plan to do just that. Is there anywhere else other than the plug on the back of the cluster I should check for dirty/loose connections?

-Lastly, the truck makes is moaning sound when accelerating. Its not very loud, just faint, but becomes more apparent as you get going faster. If you're cruising along and let off the gas, it goes away. Its hard to tell where its comming from, and I cant hear it if I stick my head out the window. I'm thinking rear end maybe? Could it be the tranny making the noise? What would you guys recommend I look first? I really don't know what this thing should sound like in the first place...

Thanks to all for any help, the forum has been an indispensable resource!

Jason

 

Good to hear you got one.. How much was she? The booster is gone if you press the brake and the pedal slowly sinks to the floor. I spent the money on higher end pads do the lines and calipers at the same time machine the rotor if it has life left that is. The sound I would think is comming from the rear end to I would replace all fluids right off the bat and filters to begin with.

 

The pedal doesn't sink, it just makes a hissing sound, and not just when you press it, the noise stays there when holding your foot steady.

I picked it up for $2500. Its a single cab, auto with only 129k miles. I got it from the original owner. Only has a little rust at the top edge of the rear fender wells. Basic bench seat but in nice shape, nice carpet and the dash isn't cracked!

Jason

 

Probably the vacuum pump making the hissing noise, or a leak, check that big vacuum line that goes from the pump to the brake booster, The brake pedal in our 91 made that hissing as you pushed it down and were hard to push when cold, our family mechanic told us it was the vacuum pump.

Change tranny fluid/filter and change rear gear oil and add limited slip solution if its a limited slip rear (look under hood on sticker). and see if it makes the moaning go away. Also it could be the u joints in the drive shaft? Your driveshaft could use a rebuild maybe. Ours was rebuilt when we bought the truck (1991 727 truck).

Pickup a nother cluster out of the boneyard if yours is looney. 89 gas cluster will work.

Hope this helps,
Brandon

 

Thanks for the suggestion. Its not a limited slip... I tested that in a parking lot! There isn't a sticker on the hood anymore, it fell off at some point. Would you be able to hear the vac pump hissing inside the cab? I assumed it was the brake booster. I'm thinking about just buying the whole booster/master cylinder assembly new just for the piece of mind.

jason

 

It will not switch to floor venting or defrost.

Mine takes a few minutes to switch especially in cold weather.

Is there a big vac canister behind the dash that controls some flaps?

If I remember there are some smaller vacum things to move the flaps under the dash, most of the time I've had this problem the vacum hoses were broken off under the hood where they go the dash, three little hoses if my memory serves. I've fixed them by permetexing them back into the control valve or whatever it is they go into, be careful not to get permetex into the hose.

-When I got the truck, none of the gauges worked, but on the way home they stared reading and have been reading since then. I read through the gauge cluster refresh sticky, and plan to do just that. Is there anywhere else other than the plug on the back of the cluster I should check for dirty/loose connections?

Check your grounds, the body ground on these trucks suck. The wire that goes from the neg post on the bat to the core support is it. I've run extra grounds for the body and has helped with electrical gremlins. There is also a ground under the dash near the raido, mine had rattled loose and caused all sorts of gauge/dash problems.

 

Thanks for the reply.

I'll check the grounds, and the one under the dash for sure!

The climate control doesn't change over after any period of time. You don't hear any noise (hissing or whatever like some cars). Nothing happens.

Jason

 

The "hissing" is most likely a leak in the booster's diaphragm.

These vacuum-pumps (dual diaphragm) are pretty much bullet-proof, but the occassional bearing may decide to grind itself into powder.


I would take a hand-held gauge and test the vacuum at each diaphragm, independent of the rest of the system.

A decent diaphragm will draw around 22-27-inches-mercury, with 29 being perfect.


If you are hearing the "hiss", I figure there is an abundance of vacuum and the noise you are hearing is a pin-hole leak in the booster.



A completely bad booster will "fight against you" when the pedal is pushed and the harder you push the pedal, the harder it will push back; once you have experienced this complete failure of the booster, you will never forget how the pedal feels.

 

I think its a leak. However you can push it far enough to where it pushes back, the pedal isn't all the way to the floor, but its about 3/4 there. At that point, thats when the truck really stops hard if you push into it. The first "soft" part of the pedal travel doesn't seem to apply all that much braking force.

Jason

 

Welcome to the world of lousy brakes.

 

My wait to start and water in fuel lights do not come on when the key is in the "on" position, however they both light up in the spring loaded "start" position... Any advice on what to check first? I'm pretty sure the heater isn't working; there is no dimming of lights and the amp gauge shows no draw.

Not sure of the outside temp there but the wait to start light only comes on when the solenoids engage the heaters in the air intake..at a certain temperature..not sure, maybe less than 40F. and the water in fuel light only comes on when there is water in the fuel. So, basically, you shouldn't see either one of these lights unless the outside temperature is low or there is water in your fuel. They are probably working correctly. Good score on the truck!

 

Any pictures of truck??

 

I'll post some pics shortly. On my other trucks, the wait to start light would always come on just for a couple seconds at least.... Is it different on a first gen?

Jason

 

Well I got the vent system working this morning, the plastic line was broke off at the rubber 90 fitting on the brake booster.

I also noticed that my engine does not have the temp sensor for the heater grid. There is just a plug there. Farther back on the wire loom, there are a couple wires (purple and yellow) sticking out of the black loom that are connected together. Could that have been the wires to the sensor?

Jason

 

My info shows that the sensor wires are light blue and black.

The old trucks don't do a key-on bulb check AFAIK.