Project Thread: 1986 F250 “Farm Truck #1” Build Thread

SkylabTech86IDI said:

Unrelated picture, but my little brother found a Honda ATC-110 for a couple hundred that we scooped up.

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That looks like a 81-82 model. Normally I don't like spray can paint jobs, but that one actually looks decent. I used to be friends with a guy who did a similar paint job to his motorcycle right before the fourth of July.

SkylabTech86IDI said:

The Honda Started right up and drove around.

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Naturally. It's a Honda, the one thing that's probably more reliable than our IDIs.

SkylabTech86IDI said:

If you ask me I think the 3 wheeler slammed down on one wheel real good and bent the axle,

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A bent axle is probably more likely to cause a bad wobble when riding than a bad bearing. If it's a bad bearing (axle bearing), you can shake the back end side to side while sitting still and see the movement.

SkylabTech86IDI said:

probably could be straightened back out.

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I know it can if you can find a good machine/fab shop. I've seen it done on a four wheeler.

The clutch disk is probably legit, but its your opportunity now to replace it. If you plan on alternative fuels I'd stick with the mechanical pump, but several of the WMO guys swear by the Holley red or black.

Jesus Freak said:

The clutch disk is probably legit, but it’s your opportunity now to replace it. If you plan on alternative fuels I'd stick with the mechanical pump, but several of the WMO guys swear by the Holley red or black.

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Alt fuel set up is awhile away, and for now I think an electric pump would help with the fuel drain back issue until I’m able to fix up all of the fuel air return.

I have manual glowplugs and run them for 6-9 seconds at a time, and cranking for 10 seconds at a time in 3 bursts at best gets the motor to catch once or twice, but it doesn’t light off. I’ll keep my foot on the floor above 32F all the time when trying to start.

If I do the gasoline rag trick and no plugs, it lights right off as long as the plugs have had at least one 6-9second cycle prior to trying.

Jesus Freak said:

The clutch disk is probably legit, but its your opportunity now to replace it.

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Do you know why the input shaft would eat the friction plate up like this?

SkylabTech86IDI said:

Do you know why the input shaft would eat the friction plate up like this?

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Pilot bearing, or possibly input shaft bearing play. Or that disk has a ton of miles on it.

James

SkylabTech86IDI said:

After the 6.9 was in place, we took the forklift back home to use it to pull a running 5.0 (with working AC) out of a junked 92 f150. The forklift made quick work of pulling out the motor assembly. The story on the f150 was that the trans was bad and we found that the transmission mounts were gone.

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Then we pulled the carbed 302 out of the 78

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As you can probably guess, yup that nice ol’ 92 302 with AC is going in the bronco with a carb hot swap to get the bronco on the road this week is the goal.

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Does that bronco have the wrong rotation fan on it?

Rdnck84_03 said:

Pilot bearing, or possibly input shaft bearing play. Or that disk has a ton of miles on it.

James

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Thanks, so it sounds like I don’t need to open up the transmission and that a whole new clutch kit that includes both bearings should fix me right up.

If it’s advisable, and I want the peace of mind, I think forcing a rebuild on it would be good since it will see hard use, and I’d rather do it all myself if it’s advisable. I have no prior experience with trans rebuilds, but I have micrometers, and a 12ton press.

As they say, Better today than never!

Black dawg said:

Does that bronco have the wrong rotation fan on it?

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It was an off the shelf advanced auto fan from years ago

SkylabTech86IDI said:

Do you know why the input shaft would eat the friction plate up like this?

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Rdnck84_03 said:

Pilot bearing, or possibly input shaft bearing play. Or that disk has a ton of miles on it.

James

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It could've been driven by a cowboy! Snatching, yanking, tugging, and just plain getting wild.

SkylabTech86IDI said:

Thanks, so it sounds like I don’t need to open up the transmission and that a whole new clutch kit that includes both bearings should fix me right up.

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Input shaft bearing won't come with a clutch kit.

You should be able to grab the input shaft and check it for play in all directions.

James

IDIBRONCO said:

I think of it as OCD. It's very strange with me. I can't stand dash gauges that don't work. I also HATE not having a full set of a particular type of tool. If I need one specialty socket or wrench, I'll buy the whole set rather than just one.

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XOLATEM says...Some people...when they need a 'special' socket...they buy a whole set...others...(like me...) buy just what they need...and then have to keep up with it...like a bin with all of the 'other' special sockets...

I was just talking about this earlier....

I used to be that way...then I realized that I was gonna need a much larger tool box...and the boxes on the tool truck ...you needed to sell your Firstborn to afford them....

Pros and cons to both philosophies...at least with buying a whole set...if you come across another application...something that will not be fixed without the 'special' tool...you will have it and not be chasing down the tool man in a panic...

XOLATEM said:

..you will have it and not be chasing down the tool man in a panic...

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Thankfully, I don't have to deal with tool trucks anymore.

SkylabTech86IDI said:

Do you know why the input shaft would eat the friction plate up like this?

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Lugging the engine would hammer that hub....misfire would induce a reverse torsional load on it as well and hammer it out...and...if the hub is made outa powdered metal it would not stand up too well to the diesel pulses...

But my bet is on the lugging over a long time...most people are not really schooled on how to drive a stick unit...they just ...maybe...learn the hard way....

I have always...well, mostly thought that mechanics make the best drivers, pilots, and heavy equipment operators....

SkylabTech86IDI said:

The next short term goals:

….

fix the brakes

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…..

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SkylabTech86IDI said:

The C6 has an issue where it likes to fall out of 2nd gear and go into neutral. Still won’t go into third. The fluid looks good so I Need to check the basics like the vacuum modulator or kick down lever. Now that the trucks been driving every day over the last 4 days, it’s time to see if we can’t unlock 3rd gear.

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I looked at the trans to see why I can’t get third.

The vacuum hose looked good, and the vacuum modular looks recently new. I pulled the vacuum hose off of the back while the truck was running, and nothing came leaking out.

On the other hand the vacuum line didn’t have any suction when I put my thumb on it. The brakes are also soft and squishy and I’ve assumed the brake booster is bad up until now.

I looked in the service manual using the link that I have, but many of the appendix pages won’t load for me. Can someone share the proper vacuums one should see if I tested with a vacuum gauge?

Does anyone have a good pdf copy of the service manual?

SkylabTech86IDI said:

Can someone share the proper vacuums one should see if I tested with a vacuum gauge?

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First off...I am going to claim ignorance and humbleness and say I don't know...and I have not seen any factory data on what the vacuum should be....

But I will claim some experience with diesel calibration C-6's firsthand from the 80's and 90's...

An original diesel C-6 has a slightly different valvebody than a gas engine one...probably because of the expected operating parameters with the lower RPM's and more dwell time in each gear...and the tendency to hold the throttle closer to WFO longer...

Also...with the VRV controlling the vacuum to the Vacuum Modulator I expect that the engineers probably took into consideration the constant vacuum signal from the vacuum pump instead of the normal rise and fall busyness inherent with the gas engines...the vacuum modulator type and pin length was tailored for diesel, as well...

But...

Back in the 80's and 90's it was common for busier transmission shops to just toss in an exchange unit and try to 'adjust' it to work with the application...those that insisted on this probably had a lot of time spent on road tests and such...when they should have just custom built the original unit and had done with it.

So...what I am saying here is that the unit stands a good chance of not having the right valvebody and governor assy for the truck and engine. If it is all original then you are good for starters...

This is the long way to explain that you should adjust your expectations of what you really can achieve here...but if you are fortunate...you just might be able to get it satisfactory...

When it comes to vacuum signal to a transmission with a vacuum modulator...the size of the diaphragm and the spring tension in the can is critical to its response...newer cans have a preload adjustment...but it is a fine adjustment ...not a way to make the wrong modulator work where it is not supposed to be.

A good general rule on vacuum signal is that if your pump can muster 19-20 inches of mercury before it is regulated at the VRV then you have a good start...you might be able to get by with less...but remember that less vacuum is translated to more percieved 'load' and will delay the upshift relative to vehicle speed and throttle position.

Once the vacuum gets to the VRV it gets reduced...not increased...you have what you have going in...and it gets worked with at the VRV...it is just a matter of how much reduction it produces relative to throttle position...it varies up and down and you have some provision for adjustment there...by turning the VRV forwards and backwards.

Now to testing vacuum....first...put vise grips on the part of the vacuum line that goes to the brake booster...this eliminates the possibility of a leaking booster making you chase your tail...

If it were me...I would put two 'T's in the vacuum lines and cap 'em...one for the source vacuum and the other for the signal vacuum...check the source with a guage first and find out how the pump is doing at all RPM ranges...steady, strong vacuum...? you are good. Signal low and varies with RPM...eeennnhhhh....you are just setting yourself for a lot of test driving and frustration...

See to it that you have the correct diesel application modulator...do not rely on the kid at the parts store that can't focus on anything but his device...seek out a good transmission pro on that...

When you install the can...look to see that the pin that connects it to the valve in the case is not too long...if you have a LOT of preload...not real good...someone tried to compensate for another problem...

When you got that straight...cap the source vacuum and uncap the signal vacuum and look at that while raising and lowering the engine speed....Idle...high vacuum....WFO...low vacuum...I would consider somewhere around 17" HG to be good at idle and somewhere around 2-3-4-" Hg to be adequate at WFO...and the sweep of the guage needle should be smooth and steady relative to throttle position...

You will find this method in the shift kit instuctions provided by Transco in their diesel C-6 valvebody recalibration package...by far the best shift kit company I used to deal with..if your valvebody is not an original diesel one...their kit will enable you to convert a gas VB to a diesel one....should you find you need it...and...it makes the transmission response more forgiving...

This tape will self-destruct in one week...

Good luck...Skylabtech...