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A bit hoppy

Lolz_cats said:
How long did this thing sit? What kind of condition are the tires in? Bias ply or radials? Could be flat spots from sitting for a long period.
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100 percent THIS

not all tires are created equal. bias ply are known for "going out of round" when sitting. My buddys dad was the only bonified mechanic in the group, swears you just need to drive them and warm them up a few times and they will smooth out...


I have some Big "O" aggressive all terrains on the K5. they are about 3 years old, only have 5-6 thousand miles on them, and if the truck sits for two weeks, the "hopping" is noticeable and irritating. these tires are supposed to be radials, and they still do it. 10-20mph is most noticeable. smooths out to a less bumpy vibration, and then to an annoying drone at higher speeds. drive the truck to work one day, and the the hopping annoyingness will be gone the next day. I will go back to BFG tires when i can pull it off.
 
scouthead said:
100 percent THIS

not all tires are created equal. bias ply are known for "going out of round" when sitting. My buddys dad was the only bonified mechanic in the group, swears you just need to drive them and warm them up a few times and they will smooth out...


I have some Big "O" aggressive all terrains on the K5. they are about 3 years old, only have 5-6 thousand miles on them, and if the truck sits for two weeks, the "hopping" is noticeable and irritating. these tires are supposed to be radials, and they still do it. 10-20mph is most noticeable. smooths out to a less bumpy vibration, and then to an annoying drone at higher speeds. drive the truck to work one day, and the the hopping annoyingness will be gone the next day. I will go back to BFG tires when i can pull it off.
Click to expand...
Well this sucker definitely sat, so that could certainly be part of it. Thanks for the input.
 
Hey All, thanks for all the input! Update on this project! I can't remember if I mentioned the front brakes were rusted and the piston was stuck in the squeeze position. The emergency brake was over adjusted to make it permanently on. Got all that address. Next I changed fluid in both differentials. Front was brand new, rear was mud. No metal and the gears looked awesome, so I was happy about that.
I wanted to see how healthy the cylinders were so I started by checking the spark plugs. They were a little "carbony" so I got worried. Got new plugs, plug wires, and distributor. In the process of putting the new plug wires in I noticed that the previous owner had clocked every wire one to the counterclockwise position. When I put everything together...BOOM! The Motor started like a dream and ran sweet! I went from thinking I was pulling the motor to being VERY excited about this project!
I've taken some advice given here and ordered a front 3 pack of leaf springs and all 4 shocks all from Tough Country.
I've got all new ball joints coming as well as headers and full exhaust. No cats, but it will have mufflers.
My new nemesis seems to be my trans. When I bought the Blazer, the detent cable had been broken off the carb mount. In addressing it I realized it had been cut too short, so I had to fabricate a new bracket so that I wouldn't have to change the TV cable. But when I took it for a drive it really wasn't shifting right. It didn't seem to upshift correctly or downshift correctly.
Honestly this transmission confuses me. It seems to have a vacuum modulator and the detent cable, also there are 2 vacuum switches on the firewall that I think are transmission related. They weren't hooked to the vacuum when I got it but I hooked them up. Transmissions are definitely outside my expertise and comfort zone. I've changed a modulator before, and I will probably change this one too, but I'm not sure that's gonna solve this.

20211207_144701.jpg

20211207_144732.jpg
 
An '85 would have had a 700R4 transmission from the factory, and I have seen those vacuum switches for the torque converter lock-up. I don't remember ever seeing 2 of them, but I honestly don't know.
If it still has a 700R4, it doesn't have a vacuum modulator. The 2nd gear servo piston cover is on the right front side of the case, above the pan rail.

Glad to hear that you are making progress and it has rewarded you!
:waytogo:
 
6872xtc said:
An '85 would have had a 700R4 transmission from the factory, and I have seen those vacuum switches for the torque converter lock-up. I don't remember ever seeing 2 of them, but I honestly don't know.
If it still has a 700R4, it doesn't have a vacuum modulator. The 2nd gear servo piston cover is on the right front side of the case, above the pan rail.

Glad to hear that you are making progress and it has rewarded you!
:waytogo:
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I'm pretty sure it's still a 700R. It's absolutely caked in crud. I'm gonna have to work to clean it and find some way to identify it for sure. That's for that insight on the switch. I've never dealt with that before. I can definitely replace it to see if that helps.
 
A square pan is a 700R4, if it's square, but has one rear corner cut off, then TH350.
Make sure that after a couple of very short test drives that the transmission oil is full. Mine seem to hold oil in the dipstick tube until I move the truck around a little. Just a little bit low will make the TCC act funny.
 
if it is a 700r4 don't drive it anymore until the tv cable sorted out, if it is out of adjustment, the trans could be ruined.

changing the tv is no big deal. I had to source one from an early 90's Caprice. everyone wanted to sell me an adjustable one for any truck I asked about.

Wouldn't be surprised if turbo 350 replaced the 700r4. TH350 has kick down cable and vacuum modulator. take a picture of the pan and post it.
 
so to set the cable on that. center of the cable sheath need to be released and pushed in. There 2 different locks I remember 1 you squeeze/push a button the second is a clip that you gently pry up. Once you get unlocked push the center in. With the cable attached to carb and in the bracket, if yours is the clip style have the clip in released position, then hold the throttle wide open and close the clip. If you have the push button style all you need to do is wide open throttle.

Before you do that have a helper step on the gas pedal in the car while you check and make sure is getting to wide open throttle.

The vacuum modulator only needs manifold vacuum. You can connect straight to the manifold port behind the carb. Skip the extra stuff for time being.

If I confused you please ask for clarification, I or maybe someone else will try help.
 
Wes, thank you. I have the push button type. I have an edelbrock 1405 and the clip that goes to that. I had my buddy press the throttle open while I held the spring button. I feel like, based on what you said I limely have the cable set right now. I'll go ahead and unhook the vacuum switches on the firewall then, and I'm going to order a new modulator and make sure my fluid level is correct.
 
there is a chance that your th350 could be a lock converter type, I have never seen 1, I am guessing it would have some wiring going to the trans if it is. This might explain the extra vacuum switches
 
Ah! OK, I'll trace those switches and see if they go into the trans. Thanks for the heads up on that. If they do function with the trans I'll get new ones to make sure they aren't an issue too.
 
Well after tracing the wires, I definitely didn't need to bother hooking the vacuum lines up to those switches. They must have been for the previous 700r. The only thing going to this TH350 is the detent cable and the vacuum line to the modulator. The new modulator on the way. I realized that my dash shift indicator has overdrive, but I believe the 350 is a 3 speed. So I wonder if I can find that dash piece without overdrive on it.

20211208_125350.jpg
 
yeah you should be able to swap the prndl out for a 3 spd one. Nothing wrong with th350.
 
Jack Schmitt said:
Well after tracing the wires, I definitely didn't need to bother hooking the vacuum lines up to those switches. They must have been for the previous 700r. The only thing going to this TH350 is the detent cable and the vacuum line to the modulator. The new modulator on the way. I realized that my dash shift indicator has overdrive, but I believe the 350 is a 3 speed. So I wonder if I can find that dash piece without overdrive on it.

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I have one I can trade you
 
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