Hello All
Wondering if anyone could give me some input on what to look for on a 1985 F250 4x4 i might purchase. Common problems, parts availability, Pros and cons etc. I'm going to look at this one monday...351, C6..410 gears. 157000 miles with a rebuilt motor and trans. Its a South Western truck so I'm not to concerned about rust. He is asking 4000, but considering the trucks history, it might be a fair price, garage kept and babied, i'm told.
Thank You in advance.

Craig

 

Welcome to FTE Craig ! That's a nice looking truck. For the most part, parts availability is not bad as there are a few interchange abilities as well as aftermarket suppliers. Up here in N.E.Ohio, that's a 6k, if not more, truck all day long !

 

Welcome! I agree, nice looking truck. Where I'm at that would be $3500 to $4000. The only thing I wouldn't like is 4.10 gears with a C6, because of the freeway RPMs. But it will help that 351 pull better. I like the 351, good motor, enough torque. I got my 1986 in February, traded a 1987 Toyota 4Runner straight across. Figured if I sold the 4Runner I would start at $4200, go down to $3800. I think they got the better end of the deal, but I'm happy. Had to do a lot of work to this Ford, but she's getting there. The 4Runner had 279000 miles on it and I don't think the engine had been overhauled. My 1986 F250 had 149000 when I got it. I bought the Gem Top separately.

 

Welcome to FTE!

That is a very clean-looking truck, and the price seems quite fair. And I like the colors as they are the same, although reversed, from Big Blue. But, I agree with grumpin that the 4.10's wouldn't be to my liking. Big Blue has 3.54's and turns 2500 RPM at 65 MPH, which is hard on the MPG. So, I'm planning to install a ZF5 manual tranny as it has an overdrive gear, which will bring RPM down to 1,800 at 65 MPH. That will reduce the noise and improve the MPG.

My tires appear to be bigger than yours, which would make my RPM a bit lower, but dividing 2500 by 3.54 and then multiplying by 4.11 says that 351W will be spinning at 2,900 RPM at 65. However, there's the torque converter slippage of about 300, so it would really be 3,200 RPM. That is very high, and the engine will sound like it is racing. Actually, it will be racing. And the MPG will really suffer. In fact, I would be surprised if you could get 12 MPG out of it running at 65, and it would go south in a hurry if you tried to run faster.

If you are planning to tow with the truck, then maybe the gearing won't be a problem. But if you aren't going to work it, then I would consider re-gearing the truck. Or, changing the transmission to one with an overdrive. However, that adds to the cost - significantly.

So, maybe you should tell us how you plan to use the truck?

 

Thank You Gentlemen for replying to my post! I went and looked at this truck and although there were cosmetic issues the truck looked solid. he had removed the smog pump and equipment and the truck wouldnt idle....heard a number of vacuum leaks. I test drove it and it wouldnt shift out of 1st gear. I walked away but then he called me back and dropped his price. I might want to go look at it again, but have a couple a questions for you guys at fte There is no inspection in oklahoma, but can smog pumps be removed without much other work...and where does the transmission modulator valve vac line hook to. He seems like a very honest guy and i feel like he felt he created these issues.

 

First, where are you? I'm in Skiatook.

As for the smog pump, it can be removed w/o much other work. You do have to block off the ports into the back of the head, but that's not difficult.

And the transmission gets its vacuum from either a vacuum tree on the rear of the intake manifold or a little plastic vacuum tree on the firewall.

 

Thank you Gary I really just want this jewel to shift so i can check other things, and it would be nice if it would idle. The ports in the exhaust manifolds have all been plugged and the spare smog parts looks like a family of octopus in the bed. I really didnt have time to check vac lines...even if i new where the majors went. The truck is in Midwest city. To be honest, i like the guy, he is being deployed to Afghanistan, and if i could help him get his truck running to sell, I would.

Craig

 

So, are you in the OKC area?

 

I don't see any issues with removing the pump and plugging hoses & pipes as needed.


Most of the time the trany vac line has a short rubber hose at the valve on the back lower right hand side of the trany. It then goes to a metal line up the trany, back right hand side of the motor. Some use a short rubber hose from the metal line to the rear of the intake. Other times the metal line has a screw flare fitting that screws into a fitting on the rear of the intake.


If you can get under the truck and find the modulator valve & vac line just follow it up to the back of the motor then top side find the line and follow to the intake.
Also check the ATF level, should have checked it for color & smell, to make sure that is ok. Color should be bright red and not smell burnt.
That hopefully should get you going on the shift issue.
Dave ----

 

I'm 30 mins south of okc. I suspect all of mentioned probs happened when vac lines where pulled. Trans fluid seemed ok but couldnt idle in park to check...hmm....There was a big hard line exposed on the back of the manifold area...could have explained the the valve sucking sound? Modulator vac to intake and not carb? Thank you

 

Purcell? I used to live there.

Anyway, the big hose is usually to the brake booster. Or the PCV hose.

 

That large leaking pipe won't allow the engine to idle down; it's also possible that it is affecting vacuum enough to be the cause of the transmission not upshifting.........if the vacuum modulator 'thinks' that the engine is under load because of lowered vacuum.

 

Well, that's the problem with these old trucks. Emissions control devices (and the methods used in the 80s) are usually bad. If you live in a state that has emissions inspections it can be a real headeache. If you don't have inspection in your state, pulling and discarding the emissions control devices is usually the way to go. And pulling them off may require a carb and distributor change depending on your specific model truck. But that would still be preferred IMO.

Also, regarding the 4.10 gears. I consider that lucky. Its a "4x4" so a mild lift (2" or 3") and 33" tires would be one of my first improvements.

Good luck and enjoy.