1975 GMC Glenbrook

[pvfjr]

I finally found a large, clean container and drained the coolant. It was time to redo the intake manifold. I was under the gun last time, and had to settle for whatever generic gasket was in stock so we could stage our house for sale without the tenement out front. Well, the cheap gasket leaked oil pretty bad. I'll have a nice, thick Mr. Gasket 404 in a couple days.


I got rid of the attachments for the mechanical gauges and screwed in my new coolant and oil pressure sensors. The oil pressure sensor body interfered with the block. A riser made it interfere with the intake instead. I couldn't find a 45 degree street elbow which would've been just right, so I had to rig up this hideous contraption for now. I'll work on finding the right elbow eventually.


While I had the coolant drained, I finally finished plumbing the new heater core and got that all tidied up.

And of course, there's so much more I can't recall. I've been pretty busy, but still putting off the fiberglass job.

 

[pvfjr]

I went to address my nemesis, the roaring fixed fan. I got out the new clutch, and removed the fan blade and extended hub. Of course, it can't be simple. It appears to be a Flex-a-Lite type fan, rather than OE style. So, it won't bolt to a clutch. I ordered another fan, hopefully it'll fit OK.

 

[Matt Colie]

Paul,
Do you want an OE fan? For shipping only?
Matt

 

[tmsnyder]

A fancy flare tool like you have is on my list of wants. What model do you have?

 

[pvfjr]

Paul,
Do you want an OE fan? For shipping only?
Matt

That is a generous offer, thanks! It might depend on the shipping. I did find an Amazon Warehouse deal on a Dorman OE replacement for $3.60 with free shipping. I'm not sure how that works, but figured I don't have much to lose. I'm curious what will show up, and how trustworthy it appears.

 

[pvfjr]

A fancy flare tool like you have is on my list of wants. What model do you have?

Here's what I have. The purchase price was a bitter pill, but I'm committed to a good number of vintage projects. It came down to this and the Eastwood kit. This one has greater portability, but is a bit more fiddly to use. On-vehicle flaring is doable though with this one. Vise mounting it frees your hands and is much more pleasant.

Having flares come out perfect is pretty priceless though. It's one of my most satisfying tools to use.

 

[pvfjr]

Things were interesting today. I bid on another Phoenix coach today, as it looked really nice. It had been rear ended, but got too rich for my blood at $4350 plus fees and travel expenses. Then I find out from Billy Massey that it last sold in 2016 for $35k, so I think someone may have gotten a pretty good deal if they do the work themselves. I bet that thing has been redone top to bottom.

Then I get a text from a friend back home that had spotted 23' coach out on the highway that someone was trying to get rid of.


There was no contact info, but I got my tow-truck driving friend to head down there with me. We were able to talk to the guy doing the property clean-up, and then we loaded it up and headed home.


It's in a sad state, but it has a lot of little things that I'm missing. It was supposedly driven from CA to OR 6-7 years ago. The inside is full of trash, and it has some decent damage up front. The driver's bucket is missing, but I think it has what people call a buddy seat?



I was excited about the outdoor thermometer I could see in the original pic, but it turns out just to be the metal shell, and all the innards and lens are gone. Bummer. It won't hurt to have an extra 455/425 since they're not growing on trees anymore.

 

[pvfjr]

Oh yes, I also replaced the intake manifold tonight with new gaskets. No pics of that, but I'll have the rest of the top end back on there in no time. I can't wait to fire it back up. I've got it halfway in my shop, and have had the door stuck open for weeks! Now I find out we have mosquito problems this time of year. Great.

Hopefully the resealing of the intake is a success. That's a pain by yourself, with the engine in place.

 

[LarryW]

6-7 yrs not running? Please read this before you try to start that engine.

https://www.gmcmi.com/wp-content/uploads/2020/06/weidner-starting-engine.pdf

Especially while you've got the distributor out anyway. HTH

 

[pvfjr]

6-7 yrs not running? Please read this before you try to start that engine.

https://www.gmcmi.com/wp-content/uploads/2020/06/weidner-starting-engine.pdf

Especially while you've got the distributor out anyway. HTH

No worries here, Larry. Resurrecting old junk is one of my favorite past times. Usually they've been down for multiple decades, rather than just a few years.

It's funny though, the ones that have been down for <20 years have worse fuel problems than the ones that have been sitting for >30 years. You should smell the "gas" that dribbled out of this thing. Good grief, that was putrid.

 

[tmsnyder]

No worries here, Larry. Resurrecting old junk is one of my favorite past times. Usually they've been down for multiple decades, rather than just a few years.

It's funny though, the ones that have been down for <20 years have worse fuel problems than the ones that have been sitting for >30 years. You should smell the "gas" that dribbled out of this thing. Good grief, that was putrid.

I feel ya, I have one sitting in a field 'just in case'....

Don't tell the wife, but I'm kinda thinking of rehab'ing it 'someday'.... It's a 75 Brookhaven.

I think collecting these almost 'free' GMCs is a bit addictive. But it was either I buy it for $500 or the guy was going to scrap it. I offered him scrap money for it mostly b/c I didn't want to see it go to the scrapyard.

 

[pvfjr]

Well last night I got the fuel pump, choke, and ignition wired up, properly this time, with fuses, on IGNITION power instead of battery power, and no more extra switches you can forget to turn off. Ugh. It's pretty satisfying to switch the key on, and watch the fuel pressure gauge come up to 4.

All my fuel lines are working great on the first try. The only leak is the fuel inlet fitting at the carb. I don't dare tighten it anymore, so I think it's time for a new gasket and a closer inspection of those mating surfaces.

Today I'll be sourcing a pickup coil (pole piece) with a yellow connector. An article written by an expert suggests my pickup coil and ignition coil are mismatched, and I have a pickup with a reversed magnetic polarity. This can apparently allow the vehicle to run, but with issues. Well, this thing has a history of issues, since it has had 3 carbs and a whole pile of extra ignition parts before coming into my possession.

 

[pvfjr]

So the fuel inlet was an aftermarket part with a shorter body that allowed me to make a hard line with a 90 degree bend without hitting the water neck. This was the only way I could eliminate the rubber line. The inlet came with an external gasket that sits on the flange just under the "nut" portion. It turns out, the inlet fitting was bottoming out just about the same time the gasket started getting snug. I guess they didn't get the depth quite right. You gotta love aftermarket parts...

I was able to fix it by scrounging up an OE style nylon gasket for the tip of the inlet. This fitting wasn't designed to use that gasket, and doesn't have the lip to retain it, so I had to be careful with placement. Luckily, this should be the last time I do this. It now passes the pressure test, and the fuel system is DONE.

 

[pvfjr]

The engine fan was more of a fiasco than one could reasonably expect. The AC Delco fan's center bore was too small for the Hayden clutch. I started grinding it out, checking the fit, and grinding some more. After many iterations, I was loosing confidence that I would be able to maintain concentricity, and didn't want to create an imbalance. Then I took possession of the '78 Palm Beach, so I robbed the fan off of it. I swapped it onto my new clutch, then fished it down into the shroud and bolted it up. It was rubbing the shroud, but I figured that was because the belts were still tight and tweaking the pulley sideways a bit. I painstakingly tightened the find thread bolts with the open end wrench in a tight space, only to find out it didn't help. I have the horse collar type shroud, and the 78 didn't. The fans are different! In addition to slightly different styling, it seems the later shroud design came with a 9.75" radius, and the older design was 9.5" radius. Ugh. Now I had to go rob the fan from the 73 Painted Desert instead. I did so much fan swapping it made my head spin. I'm not even sure how many times I dropped the 1/2" wrench. I sure wish I would've had a helper today.






I had left my upper radiator hose disconnected following the intake reinstallation, until I knew I was done tampering with the front of the motor. It's been a huge pain to get to this point, but it was totally worth it once I was able to fire the engine up. Hearing that clutch kick down after the brief warmup was music to my ears. Finally, I could hear the engine instead of the fan!

 

[pvfjr]

Oh yeah, I got a '78 Palm Beach. GMC ownership has tripled in two days.

 

[pvfjr]

I nabbed the dash pot and throttle return spring bracket off the donor, and cut the dash pot portion off. That setup is back to factory now. I also noticed the donor had a horse collar bracket that I was missing, so I grabbed that too. Then I got to looking at the belt setup on my motor. I figured out why the alternator squealed--it was riding in the wrong grooves in the waterpump, power steering pump, and crank pulleys! Some dope had switched the belts around. I can't believe it went from Phoenix to here without throwing the belt! It felt good to straighten that out, but man it was a pain. Took a crescent wrench, a 1/2", 9/16", 5/8" and an 11/16" to do the belts. Not GM's finest hour. A helper would've been great here too. Too many times crawling underneath, then having to go back to the top. Annoying.

Once I was done messing with belts, I finally closed up the cooling system and filled 'er back up. I started it, and burned off some smoke from having the intake apart and handling everything.


I brought it up to temp, and got some good readings on the temperature and oil pressure gauges. Everything is working as expected.

One bad thing, the oil pressure sensor plumbing fiasco has a leak. I really need to source that 45 degree 1/8" NPT street elbow.

 

[pvfjr]

I also got the radio working today. It had intermittent battery and ground connections due to some lazy PO splicing. Then I switched it from IGN to ACC so a guy can listen to the radio without cooking the choke. Then I got it turned on and working OK, but realized they'd swapped L and R when I messed with the balance adjustment. Good grief. That'll bug me, so it'll have to get fixed. None of this is to mention the way the aftermarket speakers were "mounted".

 

[pvfjr]

While closing up the shop, my husky was causing a commotion just outside. I had to grab a light and run out there to see what was happening. He'll tangle with anything (possum, squirrel, stray cats, skunks, cougars--he's done it all).

At least this visitor found a smart place to flee, though he had nowhere to go from there.

 

[RF_Burns]

FYI, looking at your Temp gauge reading at 1/2 scale. The OEM sensor had the "normal" temp at ~1/4 mark which is strange. There is a sensor that puts the "normal" reading at 1/2 scale which it appears you have. I believe both sensor PNs are in the GMCMI Parts Cross-over book.

You may want to take the temperature at the sensor with and IR gun to be sure its normal with that reading.

Just wanted you to know.

 

[pvfjr]

FYI, looking at your Temp gauge reading at 1/2 scale. The OEM sensor had the "normal" temp at ~1/4 mark which is strange. There is a sensor that puts the "normal" reading at 1/2 scale which it appears you have. I believe both sensor PNs are in the GMCMI Parts Cross-over book.

You may want to take the temperature at the sensor with and IR gun to be sure its normal with that reading.

Just wanted you to know.

Ah, good to know. I noticed oil pressure sensors with a couple different full-scale-range values as well. Luckily I've had the motor hooked to the old analog gauges just recently, so I've got a good baseline. I feel better with "normal" being at the halfway mark. That way if anyone else is driving, anything past halfway will seem odd to them. If 1/4 is normal, it could run hot at the halfway mark without seeming strange to someone else.

I'll be adding a trans temp gauge as well, so I'll be keeping an eye on the engine and the trans with the IR gun until I know they're predictable and trustworthy.