Build thread for the 72 GMC, finally. Thanks John!

I can picture the "taller" spindle as a result of the longer lower ball joint - I get that.

I'm not seeing the re-mounted upper ball joint making the spindle taller.

I cannot visualize the upper ball joint "ball" being any further away from the spindle. I think there will be no change - assuming you are not changing to a different "taller" upper ball joint.

SkinnyG wrote: I can picture the "taller" spindle as a result of the longer lower ball joint - I get that. I'm not seeing the re-mounted upper ball joint making the spindle taller. I cannot visualize the upper ball joint "ball" being any further away from the spindle. I think there will be no change - assuming you are not changing to a different "taller" upper ball joint.

Ay Dios Mio! Me duele la cabeza!

I could see it if its currently mounted pointing up through the upper part of the spindle. Swapping it to point down would lengthen the spindle about an incheffectively.

Knowing the finny ones style, there is a well thought out plan that doesn't translate into words well, but will make sense in pictures.

Thanks for the backup!

Things are super slow around here lately. The latest slowness is due to the temperature. I can't put stuff back together unpainted and I can't paint stuff until it's warm enough. Thus, I have to wait until weekend days to actually throw around the brush.

All whining aside, the passenger side stuff has been cleaned and painted. It was a grease party under there. Apparently every fluid this thing every dropped went to the lower control arm to hang out. Degreaser, as usual, did nothing except make it wetter. I used the wire brush mess to throw it all off, then used Eastwood's Pre stuff and it all looks pretty good as I was finally able to get it painted this afternoon.

Happily, I was able to get the bumpstops off without destroying them. Unhappily, I am going to do this a side at a time to minimize confusion. Also unhappily, I can't find my drill...

Does anyone have any good suggestions for painting springs? I am pretty sure Chassis Saver isn't the best choice.

SkinnyG wrote: The arm angle doesn't matter, it's the location of the inner and outer pivots. I could have an upper arm shaped like a dollar sign ($) - the location of the inner and outer pivots do not change.

The angle does matter. What this means is the relationship vertically of the inner and outer pivot points of the control arm. Imagine the extreme case of a vertical upper control arm. In this arrangement, the entire movement of the suspension would be translating the upper balljoint inwards. Likewise, a small inclination from stock will result in a similar improved camber gain in bump. Try it with paper dolls like I did. I won't be getting enough resolution to gather any real data, but I definitely will be making an improvement.

Now to figure out how to get twin piston D52 aluminum calipers into the budget.

Curses.

I just realized that I need to paint the U bolts and drill out the new hole in the lower control arm shaft for the increased caster. I may have missed the opportunity for reassembly this week based on temperature alone. If so, I'll store this side and tear the drivers side apart.

Well, sorta. It's already been apart and I reassembled it to measure the camber gain with my iphone as I wasn't trusting the paper dolls (which turned out to be perfectly accurate).

tuna55 wrote:

SkinnyG wrote: The arm angle doesn't matter, it's the location of the inner and outer pivots. I could have an upper arm shaped like a dollar sign ($) - the location of the inner and outer pivots do not change.

....Now to figure out how to get twin piston D52 aluminum calipers into the budget.

So, just to be clear. How much of the front end work is "Project Scope Creep" and not included in the original project plan/budget?

Why are you concerned about using the Chassis Saver on the coil springs? It would have been my first choice.

NOHOME wrote:

tuna55 wrote:

SkinnyG wrote: The arm angle doesn't matter, it's the location of the inner and outer pivots. I could have an upper arm shaped like a dollar sign ($) - the location of the inner and outer pivots do not change.

....Now to figure out how to get twin piston D52 aluminum calipers into the budget.

So, just to be clear. How much of the front end work is "Project Scope Creep" and not included in the original project plan/budget? Why are you concerned about using the Chassis Saver on the coil springs? It would have been my first choice.

Everything done so far has pretty much mirrored the rear suspension, which fits the mantra of GM+ which I try to adhere to. The calipers only came to mind after I had to remove them and realized how heavy they are.

I was initially worried about the Chassis Saver flexing off, but I suppose that's not very likely. Maybe I ought to invest in another color!

Nah, make everything black.

Then make random colored spots and marks on the underbody / suspension with different colored paint pens and spraypaint cans. People will think it is a factory fresh restoration.

iadr wrote:

tuna55 wrote: The caster angle does good things but obviously the angle is shallow on this truck. At mid corner, the camber gain is closer to half of a degree per inch of compression. Not too bad actually.

Are you sure? That's what rate of Cambar gain the new spendy scratch built Protouring musclecar front end conversions reach, and more than a Miata (to keep it semi topical...for around here)

Wow that's surprising! It might be even more with the relocated upper balljoint, I shall measure when I am complete. Not much to report tonight. I missed some spots with my rush painting session over the weekend, so it's not just the U bolts, which could have potentially ben painted inside, but the control arms too. I can't pull that off in the kitchen, Tunawife would kill me. Not in the "wow she's really mad" kid of way, in the "Well, I guess he won't be finishing the truck since he kicked that nasty oxygen habit" sort of way. I'll have to wait for warmer weather for reassembly. Tonight, I cut the springs 3/4 coil, and mounted my new hong cheapo vice so I can drill the lower shafts for caster. I suppose next I'll degrease and prep the drivers side. The weather has to really improve before this stuff can get painted and reassembled.

Those scissors didn't have a chance!

In reply to iadr:

No worries on the threadjack. As the Tunachuckers team chats about prepping another 122, it's relevant to other interests anyway. I'd need a before/after shot though to really see what they did there. In my case, the upper control arm is mounted to both the frame and the crossmember. The crossmember is half riveted together and half bolted together. There is a stamped steel bit which has some bosses within for the studs. Changing the dimensions of those studs would be major surgery. For the track, I'd probably do it. For the street on this truck, I am just going to relocate the upper balljoint and call it enough.

More setback.

Oddly enough, the replacement lower control arms have the caster-defining divot in a different place than stock.

Now, this is favorable, but it's not as much as I want, so I believe I'll need to drill anyway. The original plan was to keep the original shafts, and I see no reason to change now. I bought the new kit just for the seals since they are not available separately. Essentially these control arms ride on metal bushings. As long as there is grease, there really isn't wear.

The upper control arms were more annoying.

Rockauto had a closeout for $5.71 for each one, and again, since the seals are not available separately, I figured that it was worth it. Too bad they were for a 3/4 ton. Kudos to Rockauto for refunding my money without asking me to ship back these heavy cheap things at all, within a few hours of my request. I still need to figure out a seal solution though, and it's not easy or cheap. Most shaft kits are far more expensive, around $20 per side, and the seals are only available NOS at $10 per. This stinks.

In reply to iadr:

That appears to be for a PV544. Similar setup, though.

Other than a little longer, what's different on the upper shafts? I can't really see any. But your local...

Dusterbd13 wrote: Other than a little longer, what's different on the upper shafts? I can't really see any. But your local...

Diameter of the bearing surface and threads. Since I need the seals, that's pretty much the only thing I care about. I'll buy more shafts I guess.

Could you do some machining/sleeving and make the seals work?

Dusterbd13 wrote: Could you do some machining/sleeving and make the seals work?

Potentially, but it would stink. The seal has to mate up with the control arm which is stamped and cannot change in size easily.

I just spent the $30 to get the new seals which happen to be attached to shafts which will get saved for the scrap yard run.

Never would have thought to cut springs with scissors.

;-)

Yeah, the handle broke but they made it through!

Thanks for bumping this. I have to figure out what else I can do since it's too cold to paint stuff. This stinks.

Its 50 in my shop and im still painting. Just takes forever to dry.

paint fumes plus kerosene heater sound dangerous...

It got sort of warm enough today, so I painted up all of the missed spots, the springs and the U bolts for the lower control arm shaft.

I finally decided that waiting to paint things sucks, and that I should just tear apart the drivers side too.

Unfortunately, I lost my 5/16" allen key and my 11/16" wrench. I have to find them in the giant mess before I can go further. That sucks.

Mad_Ratel wrote: paint fumes plus kerosene heater sound dangerous...

Paint fumes plus a Kerosene heater sounds like a fun Saturday to me.