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1970 GMC Jimmy - Grandfathers Unfinished Business

imiceman44

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I would try to borrow 4 known good tires and rims and take it for a drive first--seen many cases where the tires were at fault,even though it seemed like a worn suspension part...
He has new tires and wheels
 

diesel4me

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Must have missed that part..:doah:..seen a few new tires end up being junk too though!..
 

Dan_P

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Yea, ball joints, crossmember bolts/rivets, tie rod ends, and steering box all contribute to that.
This might be ignorant...I removed the off tires for access.
Yea, ball joints, crossmember bolts/rivets, tie rod ends, and steering box all contribute to that.

Thanks for the direction. I put truck on jacks. Pulled off tires. I pulled and shook all areas of suspension, no movement. Rubber looked good around ball joints. I can’t find anything loose or with play, nada.

Bringing me to two things. 1. Steering box. 2. Alignment.
1. Steering box is leaking. Not terrible, but if it’s causing wander then I am ready to replace. I read about red hat. Is that the way to go? Or just standard remanufactured?
2. Alignment. It’s not visually terrible. I assume it’s best to diagnose everything before doing alignment (ex: don’t want to do again after steer box).
3. New tires /rims. New stabilizer. Anything else major I am missing. Trying to do my HW before I pay for an hr of labor to do a front end inspection.

Thanks
 

bp71k5

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This might be ignorant...I removed the off tires for access.


Thanks for the direction. I put truck on jacks. Pulled off tires. I pulled and shook all areas of suspension, no movement. Rubber looked good around ball joints. I can’t find anything loose or with play, nada.

Bringing me to two things. 1. Steering box. 2. Alignment.
1. Steering box is leaking. Not terrible, but if it’s causing wander then I am ready to replace. I read about red hat. Is that the way to go? Or just standard remanufactured?
2. Alignment. It’s not visually terrible. I assume it’s best to diagnose everything before doing alignment (ex: don’t want to do again after steer box).
3. New tires /rims. New stabilizer. Anything else major I am missing. Trying to do my HW before I pay for an hr of labor to do a front end inspection.

Thanks

the shop won’t likely do anything for alignment, except toe-in. If the steering box is leaking, might as well fix that first.
 

6872xtc

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I would put the tires back on and set it down. With the weight on the tires, the steering system has resistance. Have someone rock the steering wheel back and forth with the engine off. This should show if there is something loose, that may not have shown up already.

If you don't find any problems, then I would have an alignment done as toe-in can play a decent part of how a short wheelbase vehicle handles. The only thing that can change in the alignment process when swapping out a steering box on a straight axle truck is the centering of the steering wheel. That is easily adjusted at the draglink.

You will have some play in the steering box with the engine off, but if you start the engine and check it, the amount of play will be reduced if the box is properly adjusted AND not worn out.

I have heard some good about Redhead steering, but I have no experience. I had good results from Benchworks in Phoenix on 2 boxes. I would be cautious about generic parts store remanufactured units.

Just my .02
 

Dan_P

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I learned some more. By grabbing tires at 12 and 6, I can rock the tires top to bottom. I can visibility see play in the top ball joint. Can't see movement on the bottom, but assume its probably worn too. Seems that Steering Box + Ball Joints are impacting stability/wander.

This takes me to a couple questions...
- Ball Joint Replacement. Two different shops said it's 4-5 hrs of labor to replace top and bottom ball joints on both sides. Ouch...$800-$1000 total bill...:/
What are your thoughts on tackling this on my own? Never messed with ball joints before. I dont have a press. Trying to get a sense how doable this is.

- I hate to pay $1000 on an axle that is limited to drum brakes. The truck is a 1970. I dont need to change to disc now...but hate to spend $1000 on something that isn't future proof. Do you guys see a better option to invest in a newer axle now? I am hesitant to go too crazy on scope creep. The drums are recently rebuilt and work like drums should.
 

diesel4me

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I did two trucks myself using only a 5 lb ball pein hammer and some pipes the right size at home--I had a friend I could have borrowed a C clamp ball joint press from,but I didn't need to,they came out easier than I expected..hardest part was breaking both ball joints free from the steering knuckle,that took two pickle forks and a lot of hammer blows and cussing..

It is nice to have the right tool but I got by with what I had..
 

6872xtc

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I bet that you can do it, especially with help on here!
I bought the harbor freight press years ago and just lubed the threads on the screw well. And using a hammer to pop the side of the knuckle when the press has applied pressure seems to always break them free if they don't move initially.
 

imiceman44

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I learned some more. By grabbing tires at 12 and 6, I can rock the tires top to bottom. I can visibility see play in the top ball joint. Can't see movement on the bottom, but assume its probably worn too. Seems that Steering Box + Ball Joints are impacting stability/wander.

This takes me to a couple questions...
- Ball Joint Replacement. Two different shops said it's 4-5 hrs of labor to replace top and bottom ball joints on both sides. Ouch...$800-$1000 total bill...:/
What are your thoughts on tackling this on my own? Never messed with ball joints before. I dont have a press. Trying to get a sense how doable this is.

- I hate to pay $1000 on an axle that is limited to drum brakes. The truck is a 1970. I dont need to change to disc now...but hate to spend $1000 on something that isn't future proof. Do you guys see a better option to invest in a newer axle now? I am hesitant to go too crazy on scope creep. The drums are recently rebuilt and work like drums should.
Are you planning on getting different gears or you have the right ratio for your tire size?
I have a front axle with disc brakes that just had the ball joints done but you might need different gears in it.
It will be a straight bolt on for you otherwise and I can give you a good price on it.
 

Dan_P

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I hope everyone is doing well during lockdown. Good time for wrenching I suppose :)

If you've been following along, you know this truck is from my Grandfather after he unexpectedly passed away. I'm trying to piece some things together that are incomplete/partially done/ modified / etc.

Today's question is around the radio.
- The radio is original. Truck has a speaker behind the driver and passenger seats. Interestingly there are 2 audio jacks that feed from the back of the radio into the glove box.
- When the upholstery was done my grandpa wired new speaker wire up towards the radio.
- Radio does not power on.

There is free wiring that I'm not familiar with. Can you guys give me some insight to what these wires / connectors are?
- Obviously I know the L and R speaker wires.
- Red goes to fuse box.
- Do you know what the green and black wires are / go to?
- Do you know if this black connector plugs in somewhere?
- Where do I attach the speaker wires?

For now I'd like to get the radio wired up. Then see out what the audio jacks in glove box do. Then see if the original AM works.

Thanks!

Radio1.jpg

radio2.jpg

Radio3.jpg
 

diesel4me

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The black plug in the second picture is for the original radio..
Those other plugs in the third picture look like the antenna coax plug--normally a stock radio would only have one..
I suspect the radio isn't the original one-might be a factory Delco one ,but from a different year vehicle..

The black plug has the 12V power feed & the speaker outputs on it,going by original AM radios I have had in GM vehicles in the past--its been decades since I looked at one,I think there might be only one speaker power wire on the plug and the other speaker lead goes to ground..

I think I still have a Delco am radio from a '67 Impala I had--I can look at it,I am pretty sure the wiring diagram is stamped right into the sheet metal casing on the radio itself next to the socket for the black plug..it'll say 12V+, SPKR,and the third wire I cant recall if its for the dial lamp or another speaker lead..

This site has a lot of info on the various factory radios used--the one in a 72 K5 should be like the ones they show for the 60's and some early 70's models..Ray's Chevy Restoration Site -- Chevrolet Radio Information
 

Dan_P

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The black plug in the second picture is for the original radio..
Those other plugs in the third picture look like the antenna coax plug--normally a stock radio would only have one..
I suspect the radio isn't the original one-might be a factory Delco one ,but from a different year vehicle..

The black plug has the 12V power feed & the speaker outputs on it,going by original AM radios I have had in GM vehicles in the past--its been decades since I looked at one,I think there might be only one speaker power wire on the plug and the other speaker lead goes to ground..

I think I still have a Delco am radio from a '67 Impala I had--I can look at it,I am pretty sure the wiring diagram is stamped right into the sheet metal casing on the radio itself next to the socket for the black plug..it'll say 12V+, SPKR,and the third wire I cant recall if its for the dial lamp or another speaker lead..

This site has a lot of info on the various factory radios used--the one in a 72 K5 should be like the ones they show for the 60's and some early 70's models..Ray's Chevy Restoration Site -- Chevrolet Radio Information

Thanks for the info. Sounds like I need to pull the radio out to access the rear and plug in that Connector + Speaker wires? I was hoping it was accessible without removal but it doesn't look like it.
You might be right about the radio. Pic below. I assumed it was original, but no reason to believe that to be true.

Thanks for the Ray's link.

Radio4.jpg
 

bp71k5

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Radio looks original. The extra antenna plug might be for a second radio, maybe a CB trying to share the antenna or something weird like that?

might search for the other end and see if it’s even connected to anything.
 

Dan_P

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Radio looks original. The extra antenna plug might be for a second radio, maybe a CB trying to share the antenna or something weird like that?

might search for the other end and see if it’s even connected to anything.
Regarding the 2 plugs in the glove box, I think you're right...it is something weird like that.
- One plug from the glove box runs to the radio.
- The other plug from the glove box runs to the antenna.

No idea if he had a CB or something. No signs of it when I got the car.
 

diesel4me

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There was an aftermarket "splitter" that allowed you to hook up a CB to the radio antenna...it had a diode in it I think,so the CB wouldn't back feed into the radio and fry the output transistors..
I think I still have one in my dusty collection of old CB's..

That radio does "look" original,but I suspect it may be a re-pop ,most every GM car & truck I had back in the day were Delco radios..like the ones pictured in that link I posted..
Never saw one like that..
If it is original,its a very rare unit..perhaps when you get it out you might find a tag or name stamped in the case to ID it..
 

bp71k5

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There was an aftermarket "splitter" that allowed you to hook up a CB to the radio antenna...it had a diode in it I think,so the CB wouldn't back feed into the radio and fry the output transistors..
I think I still have one in my dusty collection of old CB's..

That radio does "look" original,but I suspect it may be a re-pop ,most every GM car & truck I had back in the day were Delco radios..like the ones pictured in that link I posted..
Never saw one like that..
If it is original,its a very rare unit..perhaps when you get it out you might find a tag or name stamped in the case to ID it..

they aren’t very rare unless they are AM/FM. Can find AM radios on eBay all day long for cheap. I had a couple I tore apart to see if I could add an audio input jack, but gave up. That looks like a normal AM radio of that era.
 

Dan_P

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Been a few months since posting, but getting back to some work on the Jimmy. Two questions I'm hoping for some guidance.

1. I got the ball joints replaced (as discussed earlier). 50 miles in the passenger lower right boot split (see picture 1). Replaced it under warranty and after a little bit of driving it looks to be deformed (picture 2) and different than the driver side lower boot (picture 3). Am I just paranoid or does something look off on the lower right? Any recommendations on a remedy (if something is wrong)?
- Pic 1: Passenger lower ball joint with split boot after first install.
- Pic 2: Passenger lower ball joint after it was replaced. Looks deformed.
- Pic 3: Driver side lower ball joint. For reference only.
Hoping to prevent an issue before it occurs, diagnose a different issue if it exists, or (hopefully) get peace of mind.

2. You guys aware of a good HEI install thread? Seems like it should be on here somewhere but I struggled to find a thread that walks through the process. I have some help to install it but hoping to leverage any learnings if someone already has a thread I can follow.

pic1.jpg

pic2.jpg

pic3.jpg
 
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