What did you do to your OBS GMT400 Tahoe/Yukon Today?

[Guitarded]

Minor stuff this past week. Did an oil change. Noticed a couple of areas that looked like they were sweating a little, so just fixed them. Oil filter adapter, dipstick tube. Also changed out the waterpump, as it had a noticeable drip. Nothing on my driveway, but it was definitely leaking. So not any more.

Noticed that the passenger side axle seal is sweating too, so will have to replace that in spring.

So unfortunately, nothing fun.

 

[My99Yukon]

Power Steering Fluid Drain and Fill

While chasing down a small drip on the driveway, it seemed like the front seal on the steering gearbox connecting the pittman arm was leaking. It is probably due for a new seal kit but that is for another day.

Here was my process:

1. I used a fluid exchange hand pump to suck the old, dirty fluid out of the steering pump reservoir,
   
2. filled it back to the top with new Lubeguard Synthetic Power Steering Fluid
3. started the engine and turned the steering wheel lock to lock a few times to circulate the old and new fluid
   
4. shut the motor off
5. sucked the fluid out of the reservoir again
6. repeat process three times
7. Added some Lucas Stop Leak
8. Topped off fluid level

Assuming that 60% of the fluid is in the reservoir, this should get about 97% of the old fluid out of the system. This is a safe method without the risk of running the pump dry or needing to crack the return line. Plan on burning through about 3 quarts with a bit left over for good measure.

Clean fluid, no leaks or drips and nice smooth, quiet power steering system.

 

[My99Yukon]

Brake Master Cylinder Swap: NBS

After a routine brake flush, I was finally tired of my 21yo weak and spongy brakes. I swapped out the OEM master cylinder for an NBS unit. You need a 9/16 to 1/2" adapter for the forward line but the swap was pretty straight forward. There is a good YT video on the entire process. You can use a 2005 yukon search if needed. The part at Autozone was a
Duralast New Master Cylinder (Brake System) NM4073

• Part # NM4073
• SKU # 493917

Some final thoughts:

The rear drums have an 8mm bleeder valve. The tubing that I used seemed to fit adequately but there was always some bubbling coming through the tubing no matter how much I pumped the brakes. I reconciled that this was just pass through from the tubing and proceeded with the front wheels that have a 10mm bleeder valve. The tubing was solid on this and no extraneous bubbles. Just keep an eye for it. I didnt see any reverse flow of air back into my rear brakes so I didn't worry about it. Brake check was solid at low speeds so I assume that the bleed was effective after the master cylinder install.

The new master cylinder is a fantastic upgrade. The pedal is much more firm with a much more definite stopping point. A highly recommended upgrade without the headache of the hydroboost and pedal fitment issues. This is an easy swap.

Cost: $95 for the master cylinder, $25.00 for 3 qts of synthetic brake fluid. Done.



The part comes with a bleed kit so you don't have to bench bleed. You can just use the brake pedal to clear the air out of the master cylinder before you hook up the lines and do a final bleed at the wheels. Cheers.

 

[My99Yukon]

Duplicate deleted

 

[Sam Harris]

Brake Master Cylinder Swap: NBS

After a routine brake flush, I was finally tired of my 21yo weak and spongy brakes. I swapped out the OEM master cylinder for an NBS unit. You need a 9/16 to 1/2" adapter for the forward line but the swap was pretty straight forward. There is a good YT video on the entire process. You can use a 2005 yukon search if needed. The part at Autozone was a
Duralast New Master Cylinder (Brake System) NM4073

• Part # NM4073
• SKU # 493917

Some final thoughts:

The rear drums have an 8mm bleeder valve. The tubing that I used seemed to fit adequately but there was always some bubbling coming through the tubing no matter how much I pumped the brakes. I reconciled that this was just pass through from the tubing and proceeded with the front wheels that have a 10mm bleeder valve. The tubing was solid on this and no extraneous bubbles. Just keep an eye for it. I didnt see any reverse flow of air back into my rear brakes so I didn't worry about it. Brake check was solid at low speeds so I assume that the bleed was effective after the master cylinder install.

The new master cylinder is a fantastic upgrade. The pedal is much more firm with a much more definite stopping point. A highly recommended upgrade without the headache of the hydroboost and pedal fitment issues. This is an easy swap.

Cost: $95 for the master cylinder, $25.00 for 3 qts of synthetic brake fluid. Done.

View attachment 266410

The part comes with a bleed kit so you don't have to bench bleed. You can just use the brake pedal to clear the air out of the master cylinder before you hook up the lines and do a final bleed at the wheels. Cheers.

Very nice! Sounds like a no brainer upgrade to me!

 

[dkknaebel]

Tim is getting ready to swap the intake manifold on Betty. Also gonna have to swap in a new AC compressor. This one pooped the bed. He replaced the tensioner and idler pulley. So much better. Less racket.

 

[dkknaebel]

Man I don't remember the last time I was a back to back poster of WDYDTYOBST. We are still keeping LKQ in business. Scored a new fender to replace the buggered up front left on Betty. While we were robbing this truck, I spied with my little eye another 120 cluster in a 2000 Escalade. Grabbed it as it has 50k less miles than the one in my truck currently and 190k was what my cluster read when I bought her. It was meant to be! Also checked out the rear bumper on the fender donor and it was mint. Had to grab that and going back tomorrow for the Class III hitch, we couldn't pull it because we only had a 22mm for the impact and couldn't fit that in there. Grabbed a 22 from the shop and in like 10 mins it will be mine. Found more red clay in Betty. I need to just soak her in a freshwater pond. Oh and found a newer style ac compressor. Gonna pay someone to do that. I think I have Tim convinced to let me drive her as my daily again. Well almost

 

[My99Yukon]

Smoking Dash Solved: New Dorman 599-007 Climate Control Module

For those who follow my build, after an exterior and engine wash, I had a smoking dash with burning rubber smell. After a bit of research, I do not think the two events were related but rather the climate control module finally gave up the ghost.

To be sure, and seeing other posting of multiple replacement of the part, I went with the $105 option without defroster, in the even that I did have a short in the system.

Here is the new control module installed:



I lose my rear window defroster capability but for now it is an inexpensive replacement option. And yes, I upgraded to the cubby and added a custom switch panel for other toggle options.

Easy part swap and the fan blows better and more precisely than the last few months so my thoughts on this failing part were confirmed.

 

[Guitarded]

This weekend I discovered that I have something to investigate.

First, -25 degrees Celcius, fires right up. So I'm happy about that.

Lots of heat in the front, but the rear roof vents are blowing cool.

Need to get that sorted out to keep the kiddies happy.

I'm hoping it's something simple, like maybe an actuator or something?

 

[Sam Harris]

This weekend I discovered that I have something to investigate.

First, -25 degrees Celcius, fires right up. So I'm happy about that.

Lots of heat in the front, but the rear roof vents are blowing cool.

Need to get that sorted out to keep the kiddies happy.

I'm hoping it's something simple, like maybe an actuator or something?

This is on the ‘99 Tahoe? If it’s anything like the newer-gen NBS, yes, the actuator is definitely suspect. I thought this was my issue, and when I dismantled the auxiliary hvac, actually found a hole in it wheee the paddle had broken, leaving the hole
It sits in, open and blowing cold air out..

I actually have a new OEM replacement box... just need to install it. [emoji1787][emoji106]

 

[nocal95-2dr-yukon]

I finally got my old 4L60E out from under the truck. New one starts going in tomorrow. I usually pull the transmission and transfer case out as a unit. This time I just slid the transfer case back and lowered the transmission. It is alot less weight to work with.