CK5
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1989 K5 - Gradual Learning

First 4x4 - learning basic maintenance / upkeep and maybe some small mods.
You probably got the order filled from a Denver warehouse. Nice!
 
Rockauto has no parts, so shipping time depends on which supplier is drop shipping after you order.
 
Umm Christmas tree still up ?????

Lights too?

Thankfully we didn't put up a super-involved Christmas light setup this year, so no. The tree is my girlfriend's fault, she keeps saying she is going to take it down... but I think I am going to just handle it this weekend. Sick of seeing it now!

Why are you replacing the booster?

Martin

Yeah, as Wes mentioned I'm hearing a pretty loud "WHOOOSH" when I step on the brakes. I played around with it and the sound is coming right from the firewall. I probably should have done more involved testing to see if the vacuum line check valve needs to be replaced or not.
 
My experience is that is normal for a vacuum booster, mounted like these are,(directly to the firewall).
When you step on the pedal, it opens up the seal on the firewall side to let atmosphere pressure in to provide the assistance.
There may be a something missing that used to muffle the sound some, but I will be curious if the function changes with the new booster.
 
Got the old booster out.

PXL_20230211_231415768.jpg

You would think with rust marks like that... that the back of the master cylinder would have been leaking. It's not the best pic but it seems dry.

PXL_20230211_231713374.jpg

Gonna keep putzing around with this thing and try to finish the install.
 
Got the installation finished. Man, getting to some of the six nuts for the booster... that was a major PITA. Also that cotter pin going through the pedal assembly... man I had no room to work under there. My back is gonna need some ice tonight.

EDIT: I still hear a slight "whoosh" when hitting on the brakes but it's not as loud or pronounced. The Blazer seems to stop faster or have more braking power. Normally when I fire it up it will fire off and immediately die unless I hold my foot on the gas pedal a little bit. After installation it fired up and idled without me hitting the gas. The idle in park sounded a little high but not as bad as it was before. Also when braking in front of my house I didn't hear the same surge that I was used to hearing.

Needs more testing to say for sure but I'm optimistic that this helped and was needed.
 
Got the installation finished. Man, getting to some of the six nuts for the booster... that was a major PITA. Also that cotter pin going through the pedal assembly... man I had no room to work under there. My back is gonna need some ice tonight.

EDIT: I still hear a slight "whoosh" when hitting on the brakes but it's not as loud or pronounced. The Blazer seems to stop faster or have more braking power. Normally when I fire it up it will fire off and immediately die unless I hold my foot on the gas pedal a little bit. After installation it fired up and idled without me hitting the gas. The idle in park sounded a little high but not as bad as it was before. Also when braking in front of my house I didn't hear the same surge that I was used to hearing.

Needs more testing to say for sure but I'm optimistic that this helped and was needed.
The whoosh is normal if it's just that, temporary.
A continuous whoosh is a leak.
 
I did some more tinkering on the Blazer yesterday...
  • I wanted to be absolutely sure that I didn't have any vacuum leaks so I finally inspected my lines as closely as I could. I found a couple of small leaks and got those fixed up.
  • I fixed up the windshield washer fluid line that went to the passenger-side windshield wiper. Mine broke a while ago.
  • I wanted to verify that my idle speed in Park was normal because it still sounded high. Also the truck died again when I tried firing it up the first time. So I may still have something going on.
    • I went down a rabbit hole on my IAC. Ended up resetting it once more.
    • I went down a rabbit hole on my TPS. Ended up cleaning the ground that it uses at the front of the intake.
  • I cleaned up my battery terminals because they were horrendously corroded. I had to chip away all of the corrosion out of my positive cable terminal.
  • I took my glove box off to peek at my ECM. I didn't dig into it much but just confirmed that the connectors were seated well. I went after this due to the chats @Wes Harden and I were having about the VSS code I was getting.
  • I tightened up my transfer case crossmember... it had loosened up badly on the passenger side.
    • The passenger-side framerail was soaked with ATF. I found that it was coming from the transfer case vent hose (that I had stuffed up into the passenger frame rail) and also from my rear driveshaft u-joint.
      • I moved the transfer case vent hose so that it was positioned more vertically. It was dripping ATF badly so I put it up vertically thinking that air would be able to escape and fluid would stay inside.
      • I saw dripping coming from my transfer case output seal, which sucks because I replaced that not too long ago. I think I need to try again and verify that the output surface on my transfer case is "flat" and not dented.
After the day was done, I drove the Blazer 15 miles to my buddy's house for a Super Bowl party. A lot of that was highway driving so I'm hoping that the IAC got some good "relearning" done on the drive. The Blazer felt pretty great on the drive aside from some light stumbling when hitting the gas after deceleration. The stuttering was less pronounced than before so I feel like I'm headed in the right direction. I am going to continue to monitor my cold starts to see if I can get going without my foot on the gas pedal.

My buddy came over and hung out while I was working and when he heard about the "fire off and dying" issue I was having he suggested that I test my fuel pressure. I've been really thinking that the engine is getting too much air (i.e. vacuum leak) and I hadn't considered that it wasn't getting enough fuel. I am going to rent a fuel pressure test kit and give it a try this week. Will let you guys know what happens.

That was a long post, so thanks for reading if you got this far. I'm feeling really good about the Blazer overall and am excited to drive it a ton this summer. If its only issues are what I talked about here then I feel like I'm in good shape.
 
Here's a photo of how loose that crossmember had gotten. You can see how soaked the frame rail is in the pic. Scary stuff. Going to pressure wash the underside of the Blazer and am going to watch those bolts for a little while to make sure they stay put.

Also, I should note that early on in this build thread someone kindly pointed out that those spacers should be on the top side of the frame rail. I thought about that yesterday when tightening everything up. It doesn't look like I would be able to do it that way because the crossmember would run into my transfer case. Essentially it looks like I need the spacers where they are because I need the room they provide.

PXL_20230212_225102978.jpg
 
The space between the crossmember and tcase is fixed by the mount, it will raise up with the crossmember.

Alright, that makes sense... thanks for responding man! I will try and get a jack or something high enough to support it so that I can swap the spacer location.
 
People space the tcase down in an attempt to make the rear driveshaft angle, after a lift "kit" is installed
This common in the direction from the big brand lift kits.
It causes other issues. The tilt on the engine makes the dust cap closer to firewall, radiator fan moves in shroud, could possibly rub. Front driveshaft has steeper angle.
 
Make to put the spacers back, but inside the frame. Get new lock nuts before you move the spacers.
 
Think of all the stuff you would have broken if that crossmember came free.
 
Hey Drew, check the trans fluid level. If the seal between the trans and t-case lets go it’s going to overfill the t-case with fluid to the point it starts puking out the vent.

There’s not many reasons that could be going on to cause fluid to puke out of the vent of the t-case besides the seal failing at the back of the trans. The normal fluid level is well below the vent so under normal operation it’s not going to come out.

I agree the spacers on the t-case cross member need to go inside the frame under the nuts.
 
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