Ownership Verified: Polishing a turd. 1973 GMC Sprint, with a side of XJ

73GMCSprint

Well-Known Member
Joined
Jun 20, 2007
Messages
917
Location
Southern UT, USA
Car(s)
1973 GMC Sprint, Buick 455/TH400; 1994 Jeep XJ 4.0
Minor progress has been made!

First though, some of the bad stuff about the car:


Rust! This area is definitely the worst cancer on the car. As far as I can tell everything else is surface rust, but who really knows. I didn't help this by starting some body work a few years ago, but the rust around this fender was already well established.



Shitty body work! Fuck some body shop in Fresno. It was done before I owned the car so there's not much I can do about it, but I actually have the invoices showing what was "done" to the car. Supposedly several dents were removed, trim holes welded, etc. etc. but NONE of it was actually done. Just a shit ton of body filler and then paint. The work I started probably sped up the deterioration, but I started it in the first place because the lousy work was already starting to crack and fall off the car at that point.

It's enough to make me question just how far I want to take this project in the end, but it might end up being a good excuse to buy a welder and learn how to use it. Any excuse to buy a new tool, right?

Now for better stuff. Arachnophobes may want to proceed with caution, however.


Gotta do the important stuff first. Wheels look much better with a little cleaning. They were badly neglected though, and there's a fair bit of pitting from leaving brake dust on them too long. They should be restorable though, if I decide to keep them. I like the old-school fat rubber look of the 15" rims on this kind of car, but there are zero performance tires available any more in the sizes I would need with a 15" rim. BFG Radial T/As and Cooper Cobra GTs are basically the only 2 options in my tire sizes. Going to a 17" or 18" rim opens up some options, and I can even get the same style wheel.


Front brakes disassembled.


Back of one rotor. Spiders/webs/egg sacs Every. Where.


Seriously. Every. Where. I don't reach anywhere I can't see on this thing unless I have gloves.


And that's why! It had a close encounter with the pointy end of a screwdriver.


Yay drum brakes! I realized I've never actually worked on drums myself, so pictures were taken so I know how to put it all back together.


And stripped down.

All rubber brake hoses were removed as well. The master cylinder will also be replaced; it's over 45 years old, so it's only a matter of time before it gives out.

I should now have everything I need to overhaul the brake system. New master cylinder, front calipers and pads, front wheel bearings and seals, wheel cylinders for the rear brakes, and new rubber hoses all the way around. The rear drums and shoes are actually in good condition, so they'll just go back on the car for now. I can always replace them easily if needed.

I'll see how much I can get back together tomorrow. It should actually be fairly easy, but those are famous last words.

Here's the reason for the year-long delay in working on the Sprint:

I picked this up a year ago for next to nothing. It needed some work itself, but I wanted something I could use to explore the many dirt roads and trails around Southern Utah, and put two car seats in. It had some major leaks when I got it, including what I was told was a leaky transmission input seal or pump, but I knew about all of it and the price was right. The transmission leak ended up being only the pan, so that was solved by straightening the flange on the pan and sealing it with the proper auto trans sealant. The engine ended up needing a valve cover gasket, distributor o-ring, oil filter adapter seal, and a new rear main seal. I did all of that myself, and it's now one of the few leak-free 4.0 Jeeps around here (although I may have spoken too soon--the front pinion seal is seeping a little now). The alternator promptly died after I bought it, so it was upgraded with a much higher amp unit from a same-year Grand Cherokee, which required some grinding of the brackets to fit the slightly larger case. The headlights were recently upgraded with housings to replace the old sealed beams, and a new harness which drastically increased the brightness. Now I don't have to drive by Braille at night.
The one major problem I've had so far was the passenger side motor mount shearing off the block, which broke a mounting boss clear off the block and left two bolts sheared off in the block. I thought I was going to be scrapping the engine and doing an LS swap (oh darn!), but I found some awesome aftermarket mounts that take advantage of 5 additional mounting points on the block, so problem solved despite losing a couple of the stock mounting points.
It's actually not as big a shitbox as it looks, though it's not so nice that I feel bad about beating on it. It's pretty sound mechanically. I've got some plans to make a reasonably capable crawler/overlander, but for now it'll stay pretty simple. The general plan is if something breaks, it'll be fixed better.
 

73GMCSprint

Well-Known Member
Joined
Jun 20, 2007
Messages
917
Location
Southern UT, USA
Car(s)
1973 GMC Sprint, Buick 455/TH400; 1994 Jeep XJ 4.0
I didn't get much done on Tuesday as I'd hoped; I decided to wait for a pressure washer to be delivered and give things a good spray-down before doing much more.

But, there was some slight progress yesterday.


New parts! There are a few odds and ends missing from the picture, but it's boring stuff like bearings and seals.


I got the new front rotors prepped with bearings and seals and installed them. The old dust caps were properly mangled, so new ones were procured.

I'll probably do the master cylinder next so I can flush the hard lines, and then get the new calipers and rubber hoses installed.
But, I'll be on the road this weekend so it'll have to wait. Hopefully I can get this done before it gets too hot. We're already up to 100F today.
 

73GMCSprint

Well-Known Member
Joined
Jun 20, 2007
Messages
917
Location
Southern UT, USA
Car(s)
1973 GMC Sprint, Buick 455/TH400; 1994 Jeep XJ 4.0
I was able to make a little more progress today. I had a minor medical procedure last week that prevented any work for a few days (no worries, nothing big at all), and I've become a wimp when it comes to working in temperatures over 100F. Temperatures dropped a few degrees and I got home from work early enough to get a few things done.

New brake hoses are installed. No pics of the rear line as it's hard enough to work above the rear axle let alone get a phone up in there. Not much to see anyway.

Then I got the new/reman front calipers installed. I had a moment of panic where i thought I had bought two right-side calipers, but it was just me being an idiot and having them backwards despite the huge "L" and "R" cast into each caliper. Pulled my head out of my butt and the calipers went on without any more fuss.



I'm giving Powerstop pads a try. Braking performance was never a strong point on this car - never dangerous, mind, just adequate - so I'm interested to see if some decent pads make a big difference.

If I'm not too lazy tomorrow I should be able to easily get the rear brakes back together, swap in the new master cylinder, and get it all bled. With some luck it'll go for a drive.
 

NotLaw

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Joined
Mar 18, 2008
Messages
448
Location
Cedar City, UT
Car(s)
'90 Saab SPG, '84 K5 Blazer, '67 Fairlane 500
I know what you mean about working in 100+ heat. I don't even like driving down your way in the summer season.
 

73GMCSprint

Well-Known Member
Joined
Jun 20, 2007
Messages
917
Location
Southern UT, USA
Car(s)
1973 GMC Sprint, Buick 455/TH400; 1994 Jeep XJ 4.0
I was indeed lazy yesterday and didn't get anything done, but today I got the rear brakes back together with new wheel cylinders.
I haven't cared too much about making the old parts look pretty. Goal #1 is simply to get it driving (safely). Anything beyond that will involve body work, and if I actually do that it will turn into a major project and most of the mechanicals will be upgraded, so at this point as long as a part is going to work without breaking, it stays as-is. Kind of Roadkill Garage-ish.


Sorry for the blurry potato pic. I didn't take any pictures of the process. It was too dirty, I was running out of light, and I was well past the swear word quota. At least they look like the picture I took before I tore them down, and there aren't any "extra" parts. On a side note, I officially hate drum brakes.
 

73GMCSprint

Well-Known Member
Joined
Jun 20, 2007
Messages
917
Location
Southern UT, USA
Car(s)
1973 GMC Sprint, Buick 455/TH400; 1994 Jeep XJ 4.0
Temps today were below 90 so I got off my butt and got the brakes done.


Out with the old. It still worked, but for how much longer? I'm pretty sure it is the original master cylinder, which would make it about 46 years old.


This looks like crap but it still works, so it stays. If it dies, at least the car will still stop, unlike with the master cylinder.


Much better. At least something on the car is shiny.


Back on the ground.

I took it out and bedded the new brake pads. It even has rear brakes now! There's still some break-in to do, but it already stops harder than ever, even better than when it was my daily driver. I'm able to lock it up now, which I had never been able to do before (fat tires had more traction than the brakes could overcome). The Powerstop pads deserve some credit, though I suppose old tires could be part of that too. Not to mention all the brake components were already 35+ years old when I was last driving it regularly.

Now I need to do some tuning. I suspect the timing isn't quite where it should be, and it might still have a vacuum leak.
And it will need tires, which potentially means wheels as well because I have exactly 2 options for tires in the current sizes: BFG Radial T/As, and Cooper Cobra GTs. Neither of these excite me as they are really not performance tires, but there aren't any tires for 17 or 18" wheels that are the same overall size and aren't truck tires, at least not without spending $3-400 per tire. So, it'll probably get the Coopers just to keep it simple and keep costs down.
The exhaust behind the headers consists entirely of rust, except the mufflers somehow. It all needs to be replaced too, though it'll be a good excuse to finally put some more aggressive sounding mufflers on it. I think the current mufflers are old Midas specials, which are pretty tame, though I have to admit they've held up well; they were on the car when I bought it. It desperately needs something nastier.

I need to decide how far to go with this too. Even if I just drive it the way it is, it needs some bodywork. And if I do the bodywork, I might as well just do the whole thing right. And since most of the non-mechanical parts for these mid-70s GM cars are unobtainium, I don't know how bad I want to go down that rabbit hole.

Maybe I'll just slap a Roadkill sticker on it and call it good.
 
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