73+ Crossmember LCA mounts

[joeydirt]

I have a 73-87 xmember that I want to swap, unfortunately at the time I was shopping for one there were little to non available in my area. The one I bought had some torch work done to get the lower control arms loose in hurry, Im guessing someone wanted the springs anyway the plates on the top side of the mount were bugered up with slag. I go one cleaned up pretty good after much time with a hammer and chisel. Itleast one of the others looks like the plate itself may have been hit with the torch(plate only not xmember). Is it safe to just drill out the rivet to remove the lower mount and make a new plate for the top than replace the rivet with a bolt?

[62chevy302]

got any pics?

[joeydirt]

Originally Posted by 62chevy302

got any pics?

[62chevy302]

looks pretty bad.that is the side that the nuts go on.

[joeydirt]

couldent I drill out the rivet and chisel off the plate and than make the same plate out of flat bar and bolt it on?

[Captainfab]

Yes you can replace that reinforcement plate and replace the rivet with a bolt. However you will have to do it in such a way that the bolt is long enough to locate the LCA shaft the same as the rivet does. I would use a grade 8 bolt.

Originally Posted by joeydirt

couldent I drill out the rivet and chisel off the plate and than make the same plate out of flat bar and bolt it on?

[joeydirt]

Originally Posted by Captainfab

Yes you can replace that reinforcement plate and replace the rivet with a bolt. However you will have to do it in such a way that the bolt is long enough to locate the LCA shaft the same as the rivet does. I would use a grade 8 bolt.

thanks
I dont have any u bolts yet any chance they fit tight enough in the holes for accurate alignment. I could just get the lca bolted on and than weld the plate on.

[jjzepplin]

Without going into too much detail or why, Some guys (& me) take that rivet out and replace with an Allen bolt as it locates the lower control arm shaft. The plate should be easily removable at that point and any irregularities could be filled with a welder and ground down.

[chevyrestoguy]

Originally Posted by jjzepplin

Without going into too much detail or why, Some guys (& me) take that rivet out and replace with an Allen bolt as it locates the lower control arm shaft. The plate should be easily removable at that point and any irregularities could be filled with a welder and ground down.

Exactly. That's what I did as well. I believe that the change from the locating rivet to an allen bolt more positively locates the cross shaft. On my front suspension (out of a '79 Suburban), the aft locating rivet on both the driver and passenger sides was barely making contact with the cross shaft. Now, with 4 allen bolts positively locating the lower shafts, it's even better than factory.

Right now, you at the perfect point of doing the caster mod that I did in my '64 build thread. You will need to find a machine shop that can duplicate the spot-face holes in your lower crossshaft. It's a very easy mod that will move the lower control arm forward 3/4" and help you gain some much-needed caster.

[joeydirt]

Originally Posted by chevyrestoguy

Exactly. That's what I did as well. I believe that the change from the locating rivet to an allen bolt more positively locates the cross shaft. On my front suspension (out of a '79 Suburban), the aft locating rivet on both the driver and passenger sides was barely making contact with the cross shaft. Now, with 4 allen bolts positively locating the lower shafts, it's even better than factory.

Right now, you at the perfect point of doing the caster mod that I did in my '64 build thread. You will need to find a machine shop that can duplicate the spot-face holes in your lower crossshaft. It's a very easy mod that will move the lower control arm forward 3/4" and help you gain some much-needed caster.

Cool thanks, Im back at it this week. How did you remove the lca shaft mount? Did you cut the head off, beat on it and thats it or did you have to drill it out

[chevyrestoguy]

If you're talking about the removal of the LCA saddle rivets, I used my small torch set and heated the rivet head cherry red and then hit the trigger and blew the head off. While it was still hot, I used an air chisel with a pointed tip to drive the stem out. I've done this quite a bit in the past, and got pretty good at doing it without damaging any adjacent metal. Another method is to use an angle grinder and a cut off wheel and grind the head flush to the crossmember and drive out the stem with an air chisel. Another method would be to drill out the center of the rivet by starting with a small bit and stepping it up until you get to the outer diameter of the rivet stem.

It's knuckle-busting work, but the results are worth it.

[tincan1966]

Here's a thought- if you've got all the control arms already off, why not just bolt them to your original crossmember?.

Seems like a lot of work being done on a part that doesn't have to be changed.
The main reason a lot of guys switch out the whole thing is so they do not have to disassemble it piece by piece.

[joeydirt]

Originally Posted by tincan1966

Here's a thought- if you've got all the control arms already off, why not just bolt them to your original crossmember?.

Seems like a lot of work being done on a part that doesn't have to be changed.
The main reason a lot of guys switch out the whole thing is so they do not have to disassemble it piece by piece.

As nice as that would be its a c20 so they dont work with the original xmember

[tincan1966]

No way of knowing what you were working on, just mentioned the crossmember swap.

So are you converting a C20 to a C10? Or Staying C20- to C20?

What year are you working on? Any info you provide can help us who are trying to help you.

[joeydirt]

Originally Posted by tincan1966

No way of knowing what you were working on, just mentioned the crossmember swap.

So are you converting a C20 to a C10? Or Staying C20- to C20?

What year are you working on? Any info you provide can help us who are trying to help you.

Ya I should have mentioned that I dident mean to sound like a smart ass. But anyway its a 66 C20 that im switching to c10 5 lug. Ive got a 73+ front and a 68ish 14 bolt rear that Im either going to get redrilled or buy new axles for

[Captainfab]

The 14 bolt didn't come out until '73, and only in the 10.5" full floating version. The semi floating 9.5" 14 bolt didn't come out until '79. Either one will be a bit wider that a typical '63 to early '70 C10 12 bolt. I would suggest just finding a '63-'70 12 bolt, and just buying the conversion axles if needed. The '71-'82 12 bolt will also work, but they are 1.5" wider than the early 12 bolts. Plus the '73 + will require cutting and welding to be able to bolt the under your truck.

Originally Posted by joeydirt

Ya I should have mentioned that I dident mean to sound like a smart ass. But anyway its a 66 C20 that im switching to c10 5 lug. Ive got a 73+ front and a 68ish 14 bolt rear that Im either going to get redrilled or buy new axles for

[joeydirt]

Originally Posted by Captainfab

The 14 bolt didn't come out until '73, and only in the 10.5" full floating version. The semi floating 9.5" 14 bolt didn't come out until '79. Either one will be a bit wider that a typical '63 to early '70 C10 12 bolt. I would suggest just finding a '63-'70 12 bolt, and just buying the conversion axles if needed. The '71-'82 12 bolt will also work, but they are 1.5" wider than the early 12 bolts. Plus the '73 + will require cutting and welding to be able to bolt the under your truck.

Its a 12 bolt, Im ordering parts for my dd and had 14 bolt on my mind

thanks

[joeydirt]

Does anyone have up close pics of where they cut out the rivet and replaced it with an allen head bolt?