1996 C1500 5.7 Bleeding the brakes - Question

[OBS Oregon]

Ok First thanks for the input. Yes I pushed the caliphers back inward with a C-clamp to make room for the new pads. (now I know thats not good to do) I did try to open the brake fluid reservoir and it appears to have some pressure built up inside. The fluid came leaking out as I pryed open one corner. Closed it back up until I can work on it this morning.

 

[OBS Oregon]

HOW did you make room in the calipers for the new, thicker pads?

In general, the worst, most-contaminated, wet, sludgy fluid in the brake system is at the lowest points--the calipers or wheel cylinders.

Did you push the pistons back into the bores, forcing crappy, contaminated brake fluid backwards through the ABS unit?

Or did you pinch the rubber brake hose closed, open the bleeder screw, and blow the contaminated fluid out the bleeder screw as the pistons went back into the bores?

Getting rid of contaminated fluid requires a brake fluid flush; and that's a great idea any time the friction materials are replaced. Clean out the plastic reservoir on the master cylinder, put in fresh fluid, bleed RR brake until fluid runs clean at the RR bleeder screw. It'll take awhile. LR should take a bit less time because the rear brake system should be clean except for the LR split behind the rear brake hose. RF will take awhile, LF about the same. But that only flushes three out of six valves in the ABS unit. To flush the other three, you'll need a scan tool capable of performing the "automated ABS bleed sequence"; the tool cycles the ABS valves and the ABS fluid pump. It gets the air and contaminated fluid out of the ABS unit, but not out of the brake system, you'd have to bleed all four brakes AGAIN to move the air and old fluid down and out the bleeder screws. GM says you need a gallon of fluid to do this properly--half-gallon before the ABS bleed, half-gallon after.

And then you hope there aren't rust particles or other debris trapped in the ABS valves that don't get flushed-out.

Ok First thanks for the input. Yes I pushed the caliphers back inward with a C-clamp to make room for the new pads. (now I know thats not good to do) I did try to open the brake fluid reservoir and it appears to have some pressure built up inside. The fluid came leaking out as I pryed open one corner. Closed it back up until I can work on it this morning.

 

[1998_K1500_Sub]

I pushed the caliphers back inward with a C-clamp to make room for the new pads. (now I know thats not good to do) I did try to open the brake fluid reservoir and it appears to have some pressure built up inside. The fluid came leaking out as I pryed open one corner. Closed it back up until I can work on it this morning.

Pop the cover off the brake fluid reservoir and, for now anyway, remove enough fluid to drop the level to the "full" mark or below.

There's no shame in simply pushing the calipers back as you did, that's how many do the job (that's how I used to do it, for many years). But doing the job "better" isn't that hard. Like @Schurkey said, the better approach is to open the bleeder before pushing the piston back, then bleed, etc.

I do try to draw the line at bleeding the ABS unit, as it creates at least a 2x increment of work. Otherwise, I've used gravity as my sole bleeding method for years, whenever I swap calipers or brake lines or simply just to "bleed".

 

[Frank Enstein]

The Earl's solo bleed bleed screws make this job 10x easier.

Brake Bleeders at Summit Racing

Shop brake bleeders, including speed bleeders, solo brake bleeders, and power brake bleeders at Summit Racing today. We’ve got the right brake bleeder in stock and ready to ship! <br />

www.summitracing.com

They are sold by size so you would need diameter, thread pitch, and overall length if you want to get them.

 

[1998_K1500_Sub]

The Earl's solo bleed bleed screws make this job 10x easier.

Brake Bleeders at Summit Racing

Shop brake bleeders, including speed bleeders, solo brake bleeders, and power brake bleeders at Summit Racing today. We’ve got the right brake bleeder in stock and ready to ship! <br />

www.summitracing.com

They are sold by size so you would need diameter, thread pitch, and overall length if you want to get them.

Nice, when required. Turns what for me has been a two-person job into a one-person job, as I don’t have a power bleeder.

Not necessary with a gravity bleed

I know you know that, just clarifying for OP.

 

[Frank Enstein]

Nice, when required. Turns what for me has been a two-person job into a one-person job, as I don’t have a power bleeder.

Not necessary with a gravity bleed

I know you know that, just clarifying for OP.

True. But with them I can flush quart of fluid in 15 minutes. By myself!

 

[OBS Oregon]

Did the brake bleed today. Based on what i found on U-tube and learned from reading these posts it was a sucess? Next job is replacing a broken leaf spring. Now how hard can that be? lol

 

[1998_K1500_Sub]

Did the brake bleed today. Based on what i found on U-tube and learned from reading these posts it was a sucess? Next job is replacing a broken leaf spring. Now how hard can that be? lol

How are the brakes? Good pedal feel?

 

[OBS Oregon]

All good for now - thanks.

 

[Schurkey]

Next job is replacing a broken leaf spring. Now how hard can that be?

Pain in the asp, on my Nova. But the problems I had there are not likely to be something that affects a GMT400. (Mostly, but not entirely because the friggin' aftermarket spring pair I bought were made incorrectly.)

Buy new U-bolts. Consider replacing the other spring and it's U-bolts at the same time. That spring has been down the same roads as the broken one. That way you don't have mis-matched rear springs--one new, one old. If you're installing "used" springs from a Treasure Yard, consider fresh bushings at each end.

U-bolt ends from an axle-swap on my '88 K1500 compared to new replacement:

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