New to me 99 Suburban: 5.7 vortec repairs

[unabashedpraise]

Brake question.

Had the rear on stands, wheels and drums off to figure out a noise in drivetrain. I was trying to get the transfer case in neutral. It wasn't working. Put my foot on the brakes, tried again, nothing. I had to leave a few minutes later.
This morning I noticed a puddle of brake fluid on the ground under the driver's side rear. The Piston had been driven partially out of its sleeve. I took it apart, many many frustrating minutes later i had it back together. When i checked the brake fluid reservoir the cap was still under a vacuum and made a suction noise when cap was removed, still 90% full.


Question: do you think I still need to bleed the brakes? Just that wheel?


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[Lykos]

If you have a good hard pedal you're good to go. If not I'd bleed that one wheel and go from there.

 

[unabashedpraise]

If you have a good hard pedal you're good to go. If not I'd bleed that one wheel and go from there.

Took a lot of doing, but bled the rear brakes, and pedal is good.



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[Lykos]

To a lot of doing, but bled the rear brakes, and pedal is good.



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A hard pedal is a happy pedal!

 

[unabashedpraise]

Unfortunately, after all I've done, the noise is still there. I think I've pinpointed the noise at acceleration/deceleration. Ring and pinion?


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[rayra]

Unfortunately, after all I've done, the noise is still there. I think I've pinpointed the noise at acceleration/deceleration. Ring and pinion?

Has it been worked on / apart? Could be the backlash. Have the cover off yet, what do the gears look like? Bad wear is pretty obvious.
Can you describe the noise, is it a low-pitched whirr that corresponds to your vehicle speed?

on the bleeding concur with just that one, as long as your reservoir fluid didn't go below the bottom. There's lots of vids for easy and cheap to make one-man bleeding kits, they work fine. Be a good idea to flush all the fluid anyway, on a really old vehicle. Did my '02 early on in my 'Hey Vortec Guys' topic and the old fluid was like octopus ink.

 

[unabashedpraise]

Unfortunately, after all I've done, the noise is still there. I think I've pinpointed the noise at acceleration/deceleration. Ring and pinion?

Has it been worked on / apart? Could be the backlash. Have the cover off yet, what do the gears look like? Bad wear is pretty obvious.
Can you describe the noise, is it a low-pitched whirr that corresponds to your vehicle speed?

on the bleeding concur with just that one, as long as your reservoir fluid didn't go below the bottom. There's lots of vids for easy and cheap to make one-man bleeding kits, they work fine. Be a good idea to flush all the fluid anyway, on a really old vehicle. Did my '02 early on in my 'Hey Vortec Guys' topic and the old fluid was like octopus ink.

The noise is a low scraping/scuffing noise. Not a whine or whirr. I can't hear it over 35-40 mph due to wind noise. Very obvious at lower speeds with the windows down. It is audible under all acceleration and deceleration. While coasting on flat roadway it is very faint, or I'm unable to hear it. Noise is only there while moving, not subject to RPM, happens in all gears. Gets louder when I downshift, I think because it the is more of a load on the drivetrain.

I plan on checking the fluid and gears tomorrow. I'm trying to get our house sold, so it's been on the back burner.


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[Buddha.]

The noise is a low scraping/scuffing noise. Not a whine or whirr. I can't hear it over 35-40 mph due to wind noise. Very obvious at lower speeds with the windows down. It is audible under all acceleration and deceleration. While coasting on flat roadway it is very faint, or I'm unable to hear it. Noise is only there while moving, not subject to RPM, happens in all gears. Gets louder when I downshift, I think because it the is more of a load on the drivetrain.

I plan on checking the fluid and gears tomorrow. I'm trying to get our house sold, so it's been on the back burner.


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Sometimes the backing plate (dust sheild?) on the brakes rusts through and gets too close to rotating bits and makes scary sounds, probably only applicable to disc brakes though.

I did the same oil cooler lines and and gaskets at the block on my s10 Blazer. What a pain that was to work on. Drivetrain from full size truck shoehorned into a compact chassis.

 

[unabashedpraise]

The noise is a low scraping/scuffing noise. Not a whine or whirr. I can't hear it over 35-40 mph due to wind noise. Very obvious at lower speeds with the windows down. It is audible under all acceleration and deceleration. While coasting on flat roadway it is very faint, or I'm unable to hear it. Noise is only there while moving, not subject to RPM, happens in all gears. Gets louder when I downshift, I think because it the is more of a load on the drivetrain.

I plan on checking the fluid and gears tomorrow. I'm trying to get our house sold, so it's been on the back burner.


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Sometimes the backing plate (dust sheild?) on the brakes rusts through and gets too close to rotating bits and makes scary sounds, probably only applicable to disc brakes though.

I did the same oil cooler lines and and gaskets at the block on my s10 Blazer. What a pain that was to work on. Drivetrain from full size truck shoehorned into a compact chassis.

I honestly thought it was the backing plate. I took a flapper wheel to the drums and plate. Maybe I'll try a bit more. I didn't have exactly what I needed before. In fact, maybe this calls for a bit of big freaking .


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[unabashedpraise]

The noise is a low scraping/scuffing noise. Not a whine or whirr. I can't hear it over 35-40 mph due to wind noise. Very obvious at lower speeds with the windows down. It is audible under all acceleration and deceleration. While coasting on flat roadway it is very faint, or I'm unable to hear it. Noise is only there while moving, not subject to RPM, happens in all gears. Gets louder when I downshift, I think because it the is more of a load on the drivetrain.

I plan on checking the fluid and gears tomorrow. I'm trying to get our house sold, so it's been on the back burner.


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Sometimes the backing plate (dust sheild?) on the brakes rusts through and gets too close to rotating bits and makes scary sounds, probably only applicable to disc brakes though.

I did the same oil cooler lines and and gaskets at the block on my s10 Blazer. What a pain that was to work on. Drivetrain from full size truck shoehorned into a compact chassis.

I honestly thought it was the backing plate. I took a flapper wheel to the drums and plate. Maybe I'll try a bit more. I didn't have exactly what I needed before. In fact, maybe this calls for a bit of big freaking .


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Did some checking on the rear end. Jacked up the rear end, took the cover off and turned the tires, driveshaft, and even put it in gear.

When the gears spin, there is a slight scuffing noise and it seems to bind a little. It will spin easily until it hits the same spot. Then it takes more force, moves through the bind, then spins easily again.




Here is a link to a video. Everytime it stopped or slowed,I was hitting the point where it binds up. Except when the car drove by...




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[NevadaLover]

Pull the c-clips and axles, then check the outer bearings while you have it apart, sounds like a bearing to me!
could be the pinion bearing but I would check the outers first!

 

[rayra]

sound slike a bearing to me too. But I think that your pinion is biting too deep into the ring gear. And it looks like the face of the ring teeth is degraded, what looks like a step where the worn area meets the rest of the ring. That worn metal would account for that paste on your rag. But I don't know much about such things.
Did you spray those gears clean? Even well drained there ought to be some heavy oil clinging to things, how much fluid came out? Runnign it low could have caused all the woe.

eta
I guess you are set up ok, looking around at various backlash info pages. So back to bearings...

 

[unabashedpraise]

sound slike a bearing to me too. But I think that your pinion is biting too deep into the ring gear. And it looks like the face of the ring teeth is degraded, what looks like a step where the worn area meets the rest of the ring. That worn metal would account for that paste on your rag. But I don't know much about such things.
Did you spray those gears clean? Even well drained there ought to be some heavy oil clinging to things, how much fluid came out? Runnign it low could have caused all the woe.

eta
I guess you are set up ok, looking around at various backlash info pages. So back to bearings...

There appeared to be full fluid, dark brown. It was a little frothy from spinning it, so I sprayed some brake cleaner to see better.

I honestly think there is a bearing issue somewhere. Pinion or carrier? Sound isn't coming from wheels, so they aren't the culprit... For now.....

I've never rebuilt a rear end. How do I know the gears are good?




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[NevadaLover]

The pics don't show any major problems with the gears, you look for any chips or wear that has pitting or damage to the wear areas of the gears, I personally always replace the spider gears but that is only my little quirk, if they look good to you then reuse them! once you get the gears out it is just a simple matter of pressing the old bearings off and new bearings on, check the wear pattern like rayra shows and you probably will not need to re-shim just re-assemble.

 

[rayra]

well it's opened and drained, so it's easy to pull it apart and find out. Pull the clips, pull the axles and check those bearings for wear / damage and if none observed dig deeper. It's just a few more bolts...
wouldn't hurt to change all those bearings sets while it is apart. You're already doing 90% of the work anyway.
Cheapest deal would be getting the replacement seals, at least then you can pull it all apart and put it back together with the same bearings, if nothing is visibly wrong with them.
It will be very easy to spot any issue, wear, slop, bluing / heat discoloration. How did the gear oil smell? Burned? Was it the bearing noise that drove you to crack it open in the first place, or did you discover the noise after you had it open? In other words how pronounced was the noise while on the road, if at all?