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It begins - '86 F250 6.9

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86Bug Truck

It begins - '86 F250 6.9

Took on our old family ranch truck a few weeks ago - more history on "new members start here" page.

Despite the first photo, it's in rough, rusty shape - but it does run.
Plan is to get it stripped down and get a list going of what to replace/restore/upgrade - so far, the list is pretty much "everything".

Bed is off, working on pulling the fuel tanks and exposing more frame.

While waiting for some extra hands to remove bed, I started stripping the cab - took 3 days of painstaking floor mat removal.

I don't really know what order is smartest, but getting things off and exposed is the route I'm going. It seems like every category I dip into (fuel system, suspension, etc.) is each its own giant project, so trying to keep chipping away.
I was worried about the frame integrity, but seems solid

The plan is to keep it reasonably stock, but I would like to improve it into a reliable driver (maybe single fuel tank, replace suspension, engine upgrades, etc.)
Never done this before, so it's a slow and sometimes overwhelming adventure.
I'll try to post orderly updates and not ask too many questions that have been answered before.

'86 F250 4X4 6.9 IDI Standard Cab Manual Trans

Periwinkle

Re: It begins - '86 F250 6.9

Looking forward to watching your progress. Definitely some ventilation between the floor pans and rockers haha. Up in Canada, that body would be considered rust-free.

1984 Ford F-150
2-wheel drive, 4-speed manual with NP435 Transmission, 3.08 Rear Axle
Inline-6, 300 with over 250,000km
Hamilton, Ontario, Canada

86Bug Truck

Re: It begins - '86 F250 6.9

Making progress, alternating between knocking off rust and working on rear wheel.

One worrisome thing: Every lug nut was resistant to removal through length of stud (like too hot to handle once off). I cleaned up the stud threads and lubricated before removing, but that didn't seem to make a difference - and they didn't want to thread back on easy either.
I've read that this may be due to deformation of the taper against the rim? I suppose new lug nuts will be in order? I plan to get new rims (not steel), so maybe I cross that bridge when it comes - I find a lot of the wheel stuff confusing right now.

Pulled the brake drum and not too bad in there - looks like maybe some cleanup and modest lubrication. I was considering the rear disc conversion, but I don't think it's an option for this particular truck.

Up next on the list will be getting the right tools to pull the hub and check wheel bearings and seals - I don't know if replacement is a given or if I might get lucky. It took me awhile, but the rear axle is a C9 3.55 (I have not confirmed ratio by spinning shaft yet) known as a "Sterling". So much to learn. This tag hasn't given me many clues.

Not sure if specific questions are better asked on a separate thread, figured I'd try here first.
Y'all have a great weekend,
Laurie

'86 F250 4X4 6.9 IDI Standard Cab Manual Trans

81-F150-Explorer

Re: It begins - '86 F250 6.9

The taper of the lug nuts can wear significantly, and should be replaced if worn.

The taper of the wheel, where the lug nuts touch the wheel, can also wear, but is not as common.

Check the treads as well. If extremely rusty, I'd replace the studs, and lug nuts.

Good Luck.

Truck: 1981 F-150 Explorer / Engine: 300-6 California MCU Feedback System / Trans: T-18 - 4 speed / 2.75 Ford Rear Axle Open Diff.

86Bug Truck

Re: It begins - '86 F250 6.9

Thanks so much! Sounds like best course is replace the lug nuts and studs. Pulled the other rear wheel this morning - same result.
I'll do some research on the thread size/pitch before ordering.

'86 F250 4X4 6.9 IDI Standard Cab Manual Trans

86Bug Truck

Re: It begins - '86 F250 6.9

Been a week and a half, thought I would post some updates.
I've primed and painted the rear frame, got new leaf springs and shocks installed.

Waiting on Timkens for rear axle/wheel bearings

Pulled the rear driveshaft this weekend, and much research/confusion about what to do with the yoke (sounds more complicated than I would have guessed to pull it out and re-install or replace). Also dawned on me after looking at other photos that this nut must have backed itself off considerably. This I suppose explains all the play (and partially a destroyed needle bearing cup in u joint). Got some Moog u joints on order.

I understand there's a longer yoke that would be an upgrade, so may just try to remove this, confirm length, and order accompanying seal and bearing.
More reading ahead, lol

Oh, but the new rims and tires are looking rad!

'86 F250 4X4 6.9 IDI Standard Cab Manual Trans

Gary Lewis

Re: It begins - '86 F250 6.9

Administrator

Frame, shocks, and springs look great! And the wheels are excellent!

The pinion nut backing off would cause serious problems in the differential as there's supposed to be a preload to prevent the gear mesh from changing. So you may be a candidate for a new ring and pinion.

And there is the long-pinion upgrade. That was done on Big Blue before I got him so I can't tell you what all was involved, but supposedly it solved a problem they were having so might be something to consider - especially if you have to replace the ring and pinion anyway.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

86Bug Truck

Re: It begins - '86 F250 6.9

Thanks for the info Gary! Even though it was bad news.
Based on the expertise and equipment involved, I'm thinking a diff rebuild is best left to a specialist, will investigate options this week.
Is there any basic diagnosing I can do in the meantime? Pull the pinion and look for damage? Or would the real evidence be inside the case itself?

Next phase is start pulling apart the front end body, d/c the cab, and somehow figure out how to get the cab lifted off. Then start again from the frame out, cleaning and identifying problems.

Happy Labor Day!
Laurie

'86 F250 4X4 6.9 IDI Standard Cab Manual Trans

ArdWrknTrk

Re: It begins - '86 F250 6.9

Administrator

Laurie, pulling the pinion involves removing both axles and the carrier+ring gear.

You could torque the pinion nut then check the backlash and turning resistance.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: It begins - '86 F250 6.9

Administrator

Jim is right, pulling the pinion is major work. And if you do it a rebuild of the diff is required as the mesh of the pinion to the ring gear has to be reset, and that is best done by a specialist.

And he is also right that you may get by with just retorquing the pinion nut. But that won't tell you if damage has been done, and if it has then further driving will eventually lead to failure.

You can pull the rear cover on that axle and inspect the ring gear to see if damage has been done. You'll want to drain the fluid out as it'll all come out when you pull the cover, and when you drain it you should look in it for metal shavings or flecks.

This might be an area for that specialist you mentioned as he'll know how to torque the pinion nut and test the backlash and resistance. Plus he'll know what to look for when he pulls the cover.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: It begins - '86 F250 6.9

Administrator

Gary Lewis wrote

You can pull the rear cover on that axle and inspect the ring gear to see if damage has been done. You'll want to drain the fluid out, when you drain it you should look in it for metal shavings or flecks.

If the pinion nut comes loose the pinion will get sucked in on overrun.
This usually means the tip chews into the carrier, and if that gash gets deep enough the carrier splits.

AMHIK.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: It begins - '86 F250 6.9

Administrator

That's exactly what I'm worried about. And why I think he should have a pro look at it. There may not have been too much damage to this point and the gears might be salvageable. Or they may be so far gone that he'll be stranded in the back of beyond if he tries to use them.

I'm certainly no pro and couldn't judge how usable they are. So I'd want a pro to make the call.

Gary, AKA "Gary fellow": Profile

86Bug Truck

Re: It begins - '86 F250 6.9

Thank everyone for the excellent advice. It's never going to be easier than right now to pull the axle and get it over to a pro for work. And probably a good time to consider upgrades alongside possible repairs.

The truck will stay pretty stock suspension-wise, and her days as a hard-using 4x4 and heavy towing vehicle are behind (I have a '12 F250 that handles all that.)

I really appreciate hearing y'all's thoughts.

I have a great local diesel mechanic who I've known for years - will hit him up tomorrow for recommendations on who can do the diff work.

Plenty of other stuff to do on this truck in the meantime...
Thanks,
Laurie

'86 F250 4X4 6.9 IDI Standard Cab Manual Trans

Gary Lewis

Re: It begins - '86 F250 6.9

Administrator

I think you are wise to have the axle checked by a pro. He may say they are old grandmothers worrying about nothing, but at least you will know.

And if he says what I think he'll say, which is that you have a problem, then you can think about the long-pinion upgrade as part of it.

Gary, AKA "Gary fellow": Profile

86Bug Truck

Re: It begins - '86 F250 6.9

Just an update for those that might be curious. Found a great diff specialist in San Antonio, dropped the axle off Wednesday, and here's what the inside looks like:

A bit of damage to the carrier from the pinion migration, not a huge deal.
While they have it, going to do a full rebuild, swap for a long pinion yoke (1350), and upgrade to a helical posi-traction unit - fix it right the first time, yeah?

Last few days I've been tearing down the front end.

Hoping to salvage that radiator core support - they don't look easy to find for an old 6.9

Y'all have a great weekend,
Laurie

'86 F250 4X4 6.9 IDI Standard Cab Manual Trans

Gary Lewis

Re: It begins - '86 F250 6.9

Administrator

I think you are doing it correctly. You'll be happy when it is done.

EDIT: You should look the radiator support over closely for cracks. It isn't unusual for them to have stress cracks and it would be a good idea to have them welded or brazed up.

Gary, AKA "Gary fellow": Profile

86Bug Truck

Re: It begins - '86 F250 6.9

Thanks Gary. I didn't have to look too closely though.

This is just below the air intake on driver side.

The hits keep on coming! LOL
Have a great weekend

'86 F250 4X4 6.9 IDI Standard Cab Manual Trans

Gary Lewis

Re: It begins - '86 F250 6.9

Administrator

Yikes! That's not good.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: It begins - '86 F250 6.9

Administrator

In reply to this post by 86Bug Truck

86Bug Truck wrote

Hoping to salvage that radiator core support - they don't look easy to find for an old 6.9

I'm convinced that somebody could make a good business around modding gas core supports with the drop to fit IDI radiators. (I doubt there's enough in it to justify a set of stamping dies a short run)

Maybe Tabco would be willing?

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

86Bug Truck

Re: It begins - '86 F250 6.9

Another update on the work.
Removed the dash and rest of interior trim (also all door glass after photo was taken)

Also pulled steering column, shaft, linkage, power steering pump, and steering gear box yesterday (and right fender). Column is on its way to DRB in VA for a rebuild. Hoping to source a Blue Top soon and still need to figure out what to order to replace the power steering pump.

Having heck finding a replacement passenger battery bracket - there wasn't much of one left in the truck.

And speaking of hard to find things - looks like the radiator has a "lean" to it?

Hope y'all's builds are going just how you want, have a great week,
Laurie

'86 F250 4X4 6.9 IDI Standard Cab Manual Trans