1981 Ford F100 Revival (Parked for 12 years)

[Jonathan]

Jonathan wrote

I am outside cleaning parts right now and got to the proportioning valve. I am not sure if there's something wrong with it or not but I can't get any flow through the rear brake side of the valve. Does it need pressure in the front part to open the rear? If I hook my compressed airline to the front in I will get air out of both front out sides. If I pull the bleeder button out it will stop all airflow in the front brakes totally. And the rear in is zero airflow to the rear out no matter what position the bleeder buttons in.

Any tips or advice? I can't get any flow to the rear and can't find a rebuild kit. Thinking about pulling it apart without having new seals ready and just see what I can do.

[rcarlisle]

Didn't something attach across the top of the radiator/support as well?  Jack screw turner?

Is there a Harbor Freight (cheap workable) jack that would replace the factory jack that would fit the original space?  

I would like to get that all back in mine at some point as well.  

[ArdWrknTrk]

The jack handle clips to the rear of the radiator support with the crank (handle) to the left (driver's) side.

I don't know of anyone selling a geared screw jack in the aftermarket.
It is time to visit a junkyard.... again.

[ArdWrknTrk]

Optional spare tire padlock?

Seems silly they would lock the carrier without a spare, but it would keep the sling from coming loose and dragging on the ground.

[Jonathan]

FuzzFace2 wrote

Looking good and now you know why we say as part of the brake system check up / rebuild to replace ALL RUBBER HOSES!

It also looks like that front rotor is a little thin.
I would have changed them out this way you know the front is 100% new.

My rotors still had meat on them but I did replace the calipers, pads & hoses up front.
Out back everything was new as I found a mess when the drums were pulled, yes the hose was changed out.

when I went to bleed my brakes I did not mess with the valve and dont think it made any difference.
What did was pressure bleeding as that was theonly way I could get any kind of pedal.
Dave ----

Thanks for the feedback Dave. Actually the rotors look good I think other then surface rust and dirt. The brake pads are thick too. I think the previous owner may of did the brakes shortly before parking it. The date code on the battery was also 2009 so I think he did some service right before putting it out to pasture for some reason. The owners daughter said they stopped driving it because they had so many other vehicles to use at the time. Normal I would replace the rotors and shoes anyway but I am trying to save money right now. I don't want to take any shortcuts but I think after cleaning up they will be fine. But I did get new calipers for the front and cylinders for the rear. The price was so cheap I didn't get a rebuild kit like I normally would.

[Jonathan]

The other day I did my first transmission test. I had both wheels jacked up in the rear when I was changing the tires so I figured I should try it for the first time. I didn't run it long but I think I should check the rear diff fluid. What fluid does it take and what is the best method to change it? This is my first vehicle that I need to do this.

When I first ran it only the drivers rear turned. So I lowered it down and then the passenger side would turn. So that works. I accidently tried to put it in park when it was still spinning because I don't have brakes and the parking brake could not overcome the idle of the truck. It made some nasty sounds and I caught it fast. Hopefully I didn't do any damage. So I turned the truck off then shifted to park. I didn't know it was still spinning on the passenger side because I couldn't see it. But I guess I should of known because of the crazy vibrations it causes.




 

[rcarlisle]

Can you tell which rear end it is?  Ford 9"? No fill/drain holes on back cover?  Does the 9" have a fill hole?   If there is one on the diff carrier on front side, put some 40 wt gear oil in it til it runs out.  Then put plug back in.  I may be off base, so others may ring in with more accurate information.

From Google search: https://www.fordmuscleforums.com/threads/nine-inch-diff-how-do-you-fill-up-with-oil.457745/#:~:text=Remove%20the%20drain%20plug%20for,of%20punching%20a%20hole.).

Also here but I didn't see the gear oil weight other than hypoid.    http://www.garysgaragemahal.com/axles--differentials.html

[ArdWrknTrk]

It's pretty obviously a 9"....



But you are way off base if you think this differential takes 40 weight, Randy.

Edit: the spec is right there too.
On pg. 17 of:  documentation/axles &  differentials/rear axles/instructions/Ford 9".
Ford calls for three liters of 80w90 gear oil, with additional friction modifiers if it is LS.

[rcarlisle]

ArdWrknTrk wrote

It's pretty obviously a 9"....



But you are way off base if you think this differential takes 40 weight, Randy.

And that's why I said "others may chime in with more accurate information".  So I'm wrong, but what is the proper weight?  And I am not an expert enough to look through the tire carrier and determine it's a 9".  We're not all experts.  

[rcarlisle]

Currie Enterprises recommends 85W-140 to provide a more correct answer.  I'd trust them - they build a lot of axles.

[ArdWrknTrk]

I posted the answer from the documents on this site.
And edited in the specific path to find it.

Do you want me to post what cross reference I used to determine what API numbers met the Ford spec?

There were no synthetic gear oils available when these trucks were built.
So you won't see any broad spectrum gear oils in Ford's documentation.
Most of us are driving pickups with less than 200hp.

Currie's recommendations are for people with drag slicks and 1000+ Hp that use their axles.
But go right ahead. You're not going to hurt a 9" with expensive hypoid.
Just don't forget the additive if yours is limited slip.

[Jonathan]

ArdWrknTrk wrote

It's pretty obviously a 9"....



But you are way off base if you think this differential takes 40 weight, Randy.

Edit: the spec is right there too.
On pg. 17 of:  documentation/axles &  differentials/rear axles/instructions/Ford 9".
Ford calls for three liters of 80w90 gear oil, with additional friction modifiers if it is LS.

What is your thoughts on using this? Does it have what I need for LS or do I need to get something separate to add? I think based on when I had both wheels up only one wheel spin I have a Limited Slip. I will try to get more details and pictures after work.

https://www.walmart.com/ip/Super-Tech-Gear-Lubricant-SAE-80W-90-1-Gallon-Bottle/16795067

[ArdWrknTrk]

The Supertech stuff is definitely not limited slip fluid, but I don't have anything against WalMart fluids.
In fact I have a five quart jug of diesel oil waiting for my chance.

Read the axle code (or the BOM stamp off the axle itself) and determine if you need friction modifiers in your gear oil.
You can buy the additive or buy a dedicated limited slip gear oil if you do.

[Jonathan]

ArdWrknTrk wrote

The Supertech stuff is definitely not limited slip fluid, but I don't have anything against WalMart fluids.
In fact I have a five quart jug of diesel oil waiting for my chance.

Read the axle code (or the BOM stamp off the axle itself) and determine if you need friction modifiers in your gear oil.
You can buy the additive or buy a dedicated limited slip gear oil if you do.

Here is what I found on the tag Jim. Took a while to get the years of grime covering it. Also looks like it may have a fill plug on the side which maybe I can pump out the old fluid. Let me know your recommendations.

[ArdWrknTrk]

It's not limited slip.
The tag would say 2L75 if it were.
So the fluid you already have is fine.  

Yes, there is a fill plug and you can suck out all the fluid.
Some people would want to pull the pig's head so they could remove any sludge.
But if there doesn't seem to be anything amiss worth inspecting I would just go right ahead and change the fluid..

Your truck will thank you!

[Jonathan]

ArdWrknTrk wrote

It's not limited slip.
The tag would say 2L75 if it were.

Yes, there is a fill plug and you can suck out all the fluid.
Some people would want to pull the pig's head so they could remove any sludge.
But if there doesn't seem to be anything amiss worth inspecting I would just go right ahead and change the fluid..

Your truck will thank you!

Thanks for the quick reply. So can I get the Super Tech Gear Lubricant SAE 80W-90 and that is all I need? Will a non limited slip still only run one wheel when both are off the ground? I had to lower one wheel to test the opposite side.

[ArdWrknTrk]

If you have both wheels off the ground will both wheels rotate the same direction if you turn one by hand?

There are a lot of things like brake drag that will cause some torque to go to the other wheel.

Do you have reason to think someone has changed the carrier without restamping the tag???
It sure looks like it has been there since it rolled off the line.

I mean..... decode the BOM if you want, but I have never found a mis-tagged rear end.
I have seen some without a tag, that don't match the door sticker, but they were obviously hotrodded.

[ArdWrknTrk]

If you're that worried about it, why not buy a gasket, pull the axles and the chunk out?

It would give you an opportunity to weld a proper drain bung in the bottom of the banjo if you did.

But this seems like digging too deep for whatever return you might get.

[Jonathan]

ArdWrknTrk wrote

If you have both wheels off the ground will both wheels rotate the same direction if you turn one by hand?

There are a lot of things like brake drag that will cause some torque to go to the other wheel.

Do you have reason to think someone has changed the carrier without restamping the tag???
It sure looks like it has been there since it rolled off the line.

I mean..... decode the BOM if you want, but I have never found a mis-tagged rear end.
I have seen some without a tag, that don't match the door sticker, but they were obviously hotrodded.

As I recall I was able to spin one wheel easy and the other felt locked. When I started the truck the one that turned spun and the other side did not. So I lowered down the side that spin and the other side would spin after lowering it down.

[Jonathan]

ArdWrknTrk wrote

If you're that worried about it, why not buy a gasket, pull the axles and the chunk out?

It would give you an opportunity to weld a proper drain bung in the bottom of the banjo if you did.

But this seems like digging too deep for whatever return you might get.

I would prefer to do the minimum to get it running with spending the least amount of money and time at this point. Of course when I run into an issue I like to do it correctly. But I am not worried about it for say. I just want to use the correct oil and change it. Trying to keep it simple.