Ford 9", truss, shave and gears

I'm building a Ford 9" for my truck, the truss and shave are almost done and i'll be installing 5.13 gears and a Detroit.

The truss is a 3 part truss, mainly cause it's easier to build that way, especially with my old school tools, also I want the center section to overlap the sides some.

Used a cardboard template and cut out a piece from some 2" x 5" x .250" wall tube.


I did the same for the other side and here's the template for the center piece


Center piece started out pretty rough looking, i'll have to get me a plasma cutter or a water jet some day!


Alot of grinding and cutting and I got it to fit pretty good


So far it's only tacked onto the housing, in a few spots. I think before I do the final weld up, i'm gonna brace up that housing and maybe pre-stress it a little, more on that later.

It's not very pretty, but it should be strong.

Now that the truss is tacked onto the other side of the housing, I think the housing is supported enough that I can shave the bottom, and not worry about the housing twisting on me when I shave it.

Thanks to XJ_ranger for showing us how he did his, that helped me alot!

I also pulled the carrier out of the third member, and then bolted the third member up to the housing, to help the housing not twist or warp.

I am doing the shave mainly because I want some thicker plate on the bottom of that housing where these always scrape and eventually can wear a hole thru that thin metal.

But it will also help on much needed clearance for the bottom of the housing.


Here i've marked the shape I want to cut out of the housing.


Then I started cutting sections out




Then i'll used the old gasket making trick of taping some cardboard over the opening, and tapping on the edges to mark the template




It's not a huge amount of clearance that I will gain, you can only shave so much and still clear the ring gear, but it's not bad.


I cut out some 1/4" plate using the template and got it fitting pretty good


Tacked it in a few areas, beat down a few corners, and then boogered some welds on there. That space on the bottom is for a piece i'll weld on the outside that protects the ring gear. I'll also weld this on the inside later and hope it doesn't leak


And that's how it looks on the bottom

I had already started on the gear install previously, but I ran into a snag, and i'm waiting for a carrier support to come in

Here's some of those steps, i'll finish up this install post soon.

First the pinion gear and the support come out the front of the housing. That bearing you see down in the housing, supports the back side of the pinion gear, and that's one of the things that make these such strong differentials.


Before pulling the carrier caps, I make sure and mark one.


Then the carrier can be removed from the housing, and once I removed the ring gear bolts, the carrier can be split to see the spider gears.

Another strength of the 9", the carrier completely surrounds the spider gears, instead of having 2 large openings in the carrier.

Also, there are 4 center spider gears on a cross shaft that looks like this "+", and 2 side spider gears that the axles go into. Much more gear surface and support to spread out the load.


A common area of damage, that pinion support is broken where the the lowest bolt is, that is the part I am waiting on.


I don't have my new pinion support yet, but since on the 9" I need to install the carrier next anyways, I might as well do that.

Unlike Dana style axles, the carrier does not have to be removed to get the pinion gear out and change pinion depth shims, that's because the pinion and the support unbolt and can be removed from the front side.

So once I have the carrier in place, I will only need to use the side adjuster nuts to move it around as I set the pinion depth and backlash, it won't need to be removed again.

But first I need to change the pinion bearing in the case. I've already cleaned up the housing and clamped it in the vise. And here you see that bearing I have already changed.


That bearing was not real tight in the case, it was retained with this wedged in clip, I used an few small screw drivers and pics to get under that clip and pop it out.


Then I drive the bearing in and then the clip right back on top of the new bearing.


Now I can press the carrier bearings on to the Detroit Locker carrier, whenever I have a bearing start to get crooked on me like this one, I release the pressure and move it over a little so the press is more centered towards the high side.


Once one bearing is on, I need to set the press up in a way that it is not pushing against that bearing, these bearing cages set a little higher then the inner race, and I could damage the cage if I pressed against it. So the lower bearing is down below the press surface on this setup.


Then after bolting on the new ring gear with loc-tite on the new cleaned bolts, and the bolts torqued in a star pattern to 60lbs, I can put the carrier in the housing.

It's a little tricky to get everything in place at once, there are bearing races on each side under the caps, I first lubed the carrier bearings and then I set the carrier with those races over the bearings, down into the housing, and then awkwardly held it in place, while I put both caps on and screwed the bolts down to where the caps were almost touching the housing.

Then I put some anti-sieze on the adjuster nuts and carefully screwed those in from each side, at the same time tightening down the cap bolts and making sure the nuts still turned freely as the cap bolts got tight.


That's all I can do for now, until I get the new pinion support I need.

I also ordered a socket thet fits those side adjuster nuts, I didn't really need it to take everything apart or screw the nuts in to this point, but when it comes time to set the carrier bearing pre-load, i'll need to torque those adjuster nuts to about 90lbs, and i'll want a socket that the torque wrench can be used on.

So I ordered one from completeoffroad.com for about $39.

nice job on the truss and shave. i shaved my 9 and absolutely love it. before it i ran an 8.25 and a 8.8 and used to get hung up all the time on the diff. i havent gotten hung up once since :thumbup:

Got the new pinion support in today, I upgraded and ordered the large bearing style. You can see the small bearing on the right, that is what my old pinion support used.

The new much bigger bearing is on the left.

That is a Timken part # - HM89443 for the larger bearing

And it replaces the small bearing part # - HM88048

Maybe tomorrow I can finish up the gear install.

Well I fear I may have a problem, I did some measurements by putting a straight edge against each axle flange and first measuring in front of the housing and behind the housing, and those measurements were equal.



But when I turned the straight edges vertical, and measured above the housing and below, the measurements were off almost a 1/4". Of course the actual measurement is magnified by measuring out away from the housing center. And this is a pretty crude way of measuring.

The measurements indicate I have some downward sag in the middle, if they are accurate. I wonder if the housing was able to spread a little, when I cut out the section for shaving it.

I feel pretty stupid that I didn't measure anything before I started hacking up the housing.

I have a few ideas for trying to make it straight when I weld the truss on.

But I fear i'm getting over my head here and don't have the measuring equipment to do this right :doh:

Any advise or ideas from the board?

That $400 Spydertrax housing is looking like a better option all the time.

Terry

Well how about this, I cut the welds loose on one side of the truss, the last one popped pretty loud when it came loose.

Now I measure less then a 32nd of an inch difference.

So it seems the truss was already warping the housing when it was welded on there. I had some pretty big tack welds on the ends.

Maybe this gives me an a good idea of how far I need to bend/pre-stress the housing before I weld it up. About a 1/4" I'm thinking.

I guess this shouldn't be very surpising, I've heard the pro's, do pre-stress housings before they weld on trusses, I guess this is why!

i dont have anything to contribute to this thread, but i thank you for all the greasy pictures

87xjco said:

Well how about this, I cut the welds loose on one side of the truss, the last one popped pretty loud when it came loose.

Now I measure less then a 32nd of an inch difference.

So it seems the truss was already warping the housing when it was welded on there. I had some pretty big tack welds on the ends.

Maybe this gives me an a good idea of how far I need to bend/pre-stress the housing before I weld it up. About a 1/4" I'm thinking.

I guess this shouldn't be very surpising, I've heard the pro's, do pre-stress housings before they weld on trusses, I guess this is why!

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when i weld on trusses, i very light tack every 2 to 3 inches where the truss touches the housing then when i weld it up i do all filling of gaps on the truss side and let it cool before i weld it solid so the pulling of the gap welds is minimal, i have also welded the housing in to a jig on the oppoiste side as the truss then follow the steps above. pre stressing is a good idea as well but dont over compensate, it sucks if you have it pulled to far the wrong way ( dont ask how i know :doh: )

Mr.OverKill said:

when i weld on trusses, i very light tack every 2 to 3 inches where the truss touches the housing then when i weld it up i do all filling of gaps on the truss side and let it cool before i weld it solid so the pulling of the gap welds is minimal, i have also welded the housing in to a jig on the oppoiste side as the truss then follow the steps above. pre stressing is a good idea as well but dont over compensate, it sucks if you have it pulled to far the wrong way ( dont ask how i know :doh: )

Click to expand...

Good to hear from someone who's done it both ways.

I think I'll support it at the ends and a jack in the middle with a little bit of pre stress, make about 1/2" long welds on the ends, let it cool, release the jack, and see if it moves.

I put the pinion assembly together, there is a crush sleeve that goes in between those two bearings and a pinion seal. There is no slingers or other pieces that go in.


I've pretty much decided that even though pinion bearing pre-load is supposed to be set without the seal installed, I am going to start installing the seal on any diff. that has a crush sleeve, and I'll just add a couple lbs. to the spec.

Otherwise, I have to tighten the pinion nut until the sleeve is crushed, then take the nut and yoke back off, install the seal, and then try to get the nut back to exactly the same position, it's tricky and easy to be off a little.

It always takes alot of force to get the crush sleeve to start crushing, so I set up the pinion support in the vise and put a pipe wrench on the yoke, and a pipe on the breaker bar and tightened very carefully, checking frequently to make sure it didn't get too tight.



So with the seal in place, I tightened it until I had 16 inch lbs. rotational force, the spec is 13 to 15.

Now I can install the pinion support into the case. and the pinion depth is set with the shim pointed out, I started with the same thickness as the one that came out


I ran into a small problem with the 5.13 ring gear, it is rubbing the rough area of the casting around the pinion bearing that is in the case. I was able to just force the ring gear a little and break off that little bit of casting so I could turn the ring gear. But later I'll take the carrier out and grind that area smooth.


So then I tightend the pinion support bolts, and kept moving the ring gear as needed so that I always had some backlash, once the pinion support bolts were tight, I adjust the carrier until I had about .005" backlash and a some preload on the carrier bearings, then ran the pattern

The coast side is strange, looks like the carrier is very deep.


The drive side looks just a little deep, makes me wonder if I was getting a good reading on the coast side.


My main concern as always is with the drive side, so I took the pinion support out and added a .001" shim, and then re-installed it and ran the pattern again. Drive side looks perfect.



I was still getting a strange pattern on the coast side, so I really put alot of pressure holding the ring gear and the turning the pinion gear to really force those gears against each other and rocked it back and forth several times. Now I see the real pattern on the coast side and it looks a little too deep, but I'm not going to sacrifice the drive side.


Once I set up the backlash and carrier bearing pre-load, i'll run the pattern again. Maybe that coast side will look better then, I hope!

For now, I'm going to disassemble everything and bolt the cast iron case back into the housing, I want it bolted up when I do all the welding for the truss, to help avoid possible warping of the housing.

Good thread. I'm doing about the same thing is about a month. Thanks for the tips. I'm planning on shaving the bottom, trussing the top and rear sides on mine.

Great tech and nice writeup. Looks like you gained a good bit of clearance.

Well it took me awhile to get back to working on this housing, but I finally have gotten some time when the frame rack is free at work.

Here's my (very) unsophisticated way of setting up my 9" housing to do all the final welding on the truss


I measured across top and bottom and before welding, the top measurement is about 1/16" less than the bottom measurement. It moved that much when I tacked the truss on the second time. It was even top and bottom before tacking on the truss.

I don't want it to move anymore, so I jacked up the center so that the measurement is 1/16" longer on the top, hoping that I was pre-stressing the housing the correct amount, and then I started welding and I kept measuring after every couple of welds were done.



Now that the welds have all cooled down and I have released the jack, I am measuring exactly even top and bottom....

YEAH!!!!! :woohoo: :woohoo:

That's a relief, I know it's not the best way for making sure the housing is straight, but I feel alot better now that i'm not measuring a 1/4" difference like I was when I first built the truss and had it tacked/partially welded on.

great write up.

Competition Engineering makes a great weld on truss that runs across the back of the 9" housing. It's not as stout as what you have there, but it is about $80 from summit and certainly about 20 fewer hours of work. When welding on the truss, weld an inch or two on each side alternating back and forth to minimize heat distortion. It's really hard to avoid tweaking that housing as it's pretty thin. On my latest 9", I cut the ends off and welded on 14Bff outers so I can run a FF axle. I had a friend of mine (Dean Reed at Peformance Crygenics) use his alignment bar and pucks that bolt into the third member where the bearings go. This bar will get everything perfectly square. It wasn't too much work to go with the FF ends and the strength I gained by doing it was immense. Of course I had to get custom length axles made, but pretty much every 9" project will require custom axles or at least nice 31 spline cromo's. I opted for 35 spline with a detroit.

good luck

Nice write up. I also admired your Harbor Freight tools. (grinder/press/jack) Sweet.

Now that the housings done, I can finish up a few details on building the center section.

I took it all apart and ground some of the casting slag off of the area with the arrow, it was rubbing the ring gear slightly.


Then I put it back together, torqued down the carrier cap bolts, and i'm torquing the adjuster nuts to 90lbs, and at the same time keeping the backlash in spec.


Here's a pic of the spanner socket I am using, now I have to just bolt on the two retainer brackets that keep those side adjuster nuts from turning, and it can be installed


A thick bead of silicone on the housing and new copper washers on the bolts


Now I just have to press on some new axle bearings and put the brakes together

got a shot from the back showing the shave?
sure is nice looking...

Thanks, not yet but I'll post one when I get it outside.

87xjco said:

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How did you know where to set the pinion angle?

Are the perches not final welded yet?