What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[Grady_Wilson]

Late yesterday I washed the Yukon and put a ceramic coating on it all over.
Hoping it will help with keeping the bugs and road grime off for our trip to WY tomorrow.

 

[89Suburban]

Did a 6 qt trans fluid transfusion through the dipstick tube. Flushed the brake system with my recently acquired Motive power bleeder. Changed the engine air filter.

 

[Charlie207]

Did a 6 qt trans fluid transfusion through the dipstick tube. Flushed the brake system with my recently acquired Motive power bleeder. Changed the engine air filter.

Those Motive bleeders are sweet.

 

[89Suburban]

Those Motive bleeders are sweet.

Took a while to get used to its quirks but yeah happy with it.

 

[j91z28d1]

Took a while to get used to its quirks but yeah happy with it.

how does it seal? I picked one up to do this hybrid. they require a full 30 psi of fluid on top of the master to run the bleed. some tsb about it, I bough it with the plastic gm cap and tossed in the metal one just incase I needed it. gotta plum in 30psi from the compressor and hope the whole thing doesn't blow up lol.

 

[Just Fishing]

I started getting a tick tick tick sound from the passenger side.
It screamed leaking exhaust manifold gasket.

Me expecting the worst, I cracked the hood with the engine running and the ticking sound going.
Then I saw it.

The front most (Easy to get to!) exaust manifold bolt was totally gone.
I poked a pick in there to be sure it didn't break off in there.
I was greeted with a nice hole and threads still intact!

I stuffed a left-over bolt from my Jeep in there for now, and a new set of ARP bolts are on order since that's what I used.
time to go through to make sure they are all tight...
I'm glad it stopped when a new bolt was installed, otherwise it's a new gasket.

 

[89Suburban]

how does it seal? I picked one up to do this hybrid. they require a full 30 psi of fluid on top of the master to run the bleed. some tsb about it, I bough it with the plastic gm cap and tossed in the metal one just incase I needed it. gotta plum in 30psi from the compressor and hope the whole thing doesn't blow up lol.

Damn that's a lot. Honestly I hate applying any pressure to the plastic tank on top of the master. I am afraid of it popping out of the mounts or the tank splitting along the plastic weld in the middle. I was running between 5-10 psi doing mine. But that's just me skitzing. It's probably fine.

The GM 3 prong cap adaptor I got with it came with 2 gaskets. I tried the thinner one first. It felt snug but it leaked. So I went with the thicker one which you really have to wrench on there but it worked and kept it sealed.

I thought you had a Tech 2 or other high end device? You can use that to bleed the brakes without the Motive bleeder.

 

[89Suburban]

I started getting a tick tick tick sound from the passenger side.
It screamed leaking exhaust manifold gasket.

Me expecting the worst, I cracked the hood with the engine running and the ticking sound going.
Then I saw it.

The front most (Easy to get to!) exaust manifold bolt was totally gone.
I poked a pick in there to be sure it didn't break off in there.
I was greeted with a nice hole and threads still intact!

I stuffed a left-over bolt from my Jeep in there for now, and a new set of ARP bolts are on order since that's what I used.
time to go through to make sure they are all tight...
I'm glad it stopped when a new bolt was installed, otherwise it's a new gasket.

You got lucky!

 

[Just Fishing]

You got lucky!

I was going to be mad if the bolt was broken off.
I spent extra $$ on ARP to hopefully prevent it.

 

[j91z28d1]

Damn that's a lot. Honestly I hate applying any pressure to the plastic tank on top of the master. I am afraid of it popping out of the mounts or the tank splitting along the plastic weld in the middle. I was running between 5-10 psi doing mine. But that's just me skitzing. It's probably fine.

The GM 3 prong cap adaptor I got with it came with 2 gaskets. I tried the thinner one first. It felt snug but it leaked. So I went with the thicker one which you really have to wrench on there but it worked and kept it sealed.

I thought you had a Tech 2 or other high end device? You can use that to bleed the brakes without the Motive bleeder.

ugh, when I test fit I didn't think the thick one would even fit. sounds like I'll have to force it and hope.


man it's such a long story with hybrid brakes, it's literally the most complicated system on the truck. think if you needed to design fly by wire brakes but 20 years before fly by wire brakes were a thing, so it's completely mechanical. the pedal doesn't actually send fluid to the calipers. that's all done by a 2000psi motor and accumulator. but to make the pedal feel normal, there's a whole brake feel cyl section. and then as a back up if the whole nonsense fails the pedal goes low enough that it bypassed all that and actually works like normal brakes sending fluid from master to caliper. throw in you charge and batteries by regen, and that needs to feel seamless as well. so that transition from regen to slowing down below regen speeds. the back brakes need to kick back in. all without feeling it. oh yeah, there's no adjustments for it. it's just gotta be perfect or you start replacing parts. parts thst are all obsolete and discontinued at this point.


but yes, gm techs have always been clueless in general but more so specifically gm hybrids and electrics. which is sad because gm was away ahead of the curve on all of it. so far ahead they gave up on it all before it became popular enough to be profitable.
they needed a tsb to tell them how to bleed the breaks and that requires a full 30psi with fluid on top while running the automatic brake bleed with the tech 2 with 2 people.

I mainly want to flush the fluid before before it causes me trouble but also be nice not to break it along with way haha.