Acceptable crossmember to e-brake drum clearance? (1 Viewer)

[pinkiedog64]

Anyone know a recommended clearance between the factory tube crossmember and e-brake drum? This is on a Feb 1970 FJ40 with 2F, SM465, plate adapter, and factory 3 speed tcase. With the extra length of the SM465 and plate adaptor, the rear of the tcase is 115mm further rearward that the original setup was and now clearance between the tube crossmember right behind the tcase and the e-brake drum is an issue. I "massaged" the crossmember with a torch and hammer to gain some clearance. Figure since the crossmember just keeps spacing between the frame rails a small amount of massaging won't hurt anything. I'm at about 1/8" right now. How much does that clearance change during wheeling? Does the frame and crossmember flex enough to eat up clearance? I don't want to go with an aftermarket crossmember.

Thanks all,

Stephan

 

[pinkiedog64]

This is what the clearance looks like right now.

 

[FishTacos]

I don't think you can give enough clearance there without significantly compromising the crossmember. I think the simple solution is to sell the sm465 and apply the proceeds to a Toyota 3 or 4 speed transmission. I have no personal experience in this area, however, so take my assessment with a grain of salt.

3 speeds are pretty cheap (~150$) and easy to come by used. H42 trans are plentiful as well.

That's what I would do but I'm not a big fan of conversions.

 

[pinkiedog64]

I just removed the stock 3 speed and rebuilt the SM465 that I installed in there. I specifically want the SM465. It won't be coming back out for a different trans. What is "enough clearance" in your experience?

 

[Living in the Past]

When I install a H42 in my 68 which is about the same length I added washers to the front motor mount which then lower it in the back. With H42 which is a overall larger transmission it help with clearance at the back of the transmission cover also. When doing this check for clearance in the radiator shroud.

 

[FishTacos]

In my experience, and like I said I don't have any with a swap like this, is that 115mm farther forward is enough. You may be fine like that because it doesn't move a whole lot. Just looks creepy. I would worry about a rock or some other durable thing getting lodged in there between crossmember and the drum. Such a circumstance could badly damage transfer, rear driveshaft, diff, or worse......cause a crash. as an alternative, you could modify the crossmember. I don't mean torch and hammer. More like tube notcher and welder.

 

[FishTacos]

LITP's solution sounds good too.

 

[Living in the Past]

While I haven't installed it yet I did buy a 73 and later torque tube to replace the one in my 68. Those were formed with a hump around the brake drum.

 

[FF LC FREAK]

I just cut the tube out and moved it farther back.

Remember, the t/c will move around a bit under torque. With how close it is now, I wouldn't be surprised if you heard a clunk every once in awhile while driving when it hits the cross member.

 

[FishTacos]

And very soon your rear seal will be toast....

 

[bikersmurf]

I've seen cross members modified so they are bolted in… with a couple of plates on each end, you could offset it enough to have 3/4-1" of clearance… which I think would be the minimum I'd want.

 

[FF LC FREAK]

I've seen cross members modified so they are bolted in… with a couple of plates on each end, you could offset it enough to have 3/4-1" of clearance… which I think would be the minimum I'd want.

Like this?

Sure makes it easy when I need to drop the transmission / transfer case.

 

[bikersmurf]

That's kinda my thought. Although, depending on the required offset, I might use 2.5" channel rather than flat bar.

Although if it was rotated 20°, perhaps no horizontal offset would be required.

 

[watrob]

You need a 1" to be on the safe side, have you thought about heating the cross member and rotating the bow back towards the rear 1", a couple oxy & acetelyne torches would create enough heat?

 

[pinkiedog64]

Thanks guys. I like the welded on plates that bolt in like Bikersmurf and FF LC Freak mentioned. Watrob, I don't think I could heat up the crossmember enough over a large enough area at a time to bend/rotate the bow rearwards. Part of it is I am simply nervous under the FJ40 with a oxy acetylene torch even though is securely on jack stands. Think I'll give cutting the crossmember out and welding on flanges like FF LC Freak did. I'll shoot for about an inch of clearance. Would be interesting to mount a GoPro aiming at the e brake drum/crossmember while driving/wheeling and see how much movement there actually is. I am definitely not comfortable with the clearance I have now. Not sure 1" is necessary, but if I'm going to the trouble of adding flanges, I can make it whatever I want I suppose. I'll keep this thread updated with the progress.

 

[Bambi Girl]

Hi
I had a similar problem with my 1982 FJ40 when fitting a 5 speed box.
The extra 100mm in length of the 5 speed box and the uni joint hit the cross member.
After a lot of debating my fix would be to cut out the cross member and rotate it about 30 deg.
I would then machine 2 pieces of hollow bar to fit the cross bar . This will give added strength when welding.
I used hollow bar as this will allow any water that may enter the cross bar drain. Solid would act like a plug.
This fix gave me over an inch of clearance.
Cheers.

...via IH8MUD app

 

[Cleg]

I had the same issue after putting the longer 4 speed transmission in place of the 3 speed in my '72.
Here is a solution that allowed for taking the cross member back off to get it out of the way if you ever need to pull out the transmission again.
I did not tilt the cross member, just left it vertical and moved it straight back 2-1/4".
Clearance to the closest piece of the drive line , the U-Joint yolk is 1-1/4" - 1-3/8"
Clearance from the E-brake drum face to the front edge of the cross member is 2-1/2" to 2-3/4"

I did this with the tub off of the frame and the transmission installed.

The steps were...
Cut the cross member off as flush with the frame rails as possible and grind the surface flat.
Cut two 4" x 6.25" rectangular plates. Your plates may be longer depending on the length of your transmission.
Clamp the plates to the frame rails and drill 4 holes in a pattern around the remaining circular hole, cut off end of the cross member that is left in the frame rail.
The holes are sized for 7/16 bolts. the lightening holes inside the frame rails allow enough access for nuts & a wrench for bolting through the rails.
The frame rails are not parallel but get wider towards the back of the truck so the addition of the two 1/4" plates allowed the cut-out cross member to fit without re-cutting the length.
Temporarily bolt the plates to the frame rails and find a way to clamp the cross member where you want it.
Tack weld the cross member to the plates.
Remove the assembly & finish welding & painting with it off of the truck.

 

[Living in the Past]

I just checked my setup and I have no problem with the brake drum. It is in front of the torque tube. I reread the first post and convert the 115 mm to inches and realized this 4 1/2" while my H42 only adding 3 1/2". I had a SM420 years ago with a early adapter plate that was thicker than the new ones. I guess the SM465 is a longer transmission than the SM420. My adapter was 1" while newer ones were 1/2". My solution was pretty simple but obviously wouldn't work here. Most all the mods shown are better done with the tub off. At the very least I would remove the gas tank before welding in this area with the tub on. Like I said I already have the later torque tube but will only replace it as part of a frame off restore.