PS Fluid=Oops...thoughts?

[Daubs]

Still trying to get the crate 350 running well. Stepped on brakes and rears locked up. Thought I had better check the fluid...Looks completely dry in front res. Should I bleed the brakes, or just fill her up and hit the road?

A picture:

[kansas city cheyenne]

If it were me, I would bleed them. You probably have lots of air in the lines. Better safe than sorry.

[truckdude239]

fill and bleed check for leaks

[Dunrollin]

I have had some success with filling, then slowly moving the pedal up and down, sometimes the air bubbles just ease out. If the fluid looks funky (yours does) the bleeding can also be a flush!

[Longhorn Man]

But this begs the question... where did the fluid go?
You better start looking for leaks.

[70rs/ss]

I might pull that master cylinder too those crusties at the bottom can make a cylinder stick. Pull the rear drums, I'll bet one is wet!

[Daubs]

I'm wondering about leaks also...haven't seen any that I can remember. I'll have to fill her up and have a look.

[Fred T]

What you see is bad news. The fluid is dirty and contaminated. If you pull the drums, you will probably find one of the cylinders leaking. At this point I would recommend rebuilding or replacing the master cylinder and both rear cylinders. I would assume the front reservoir is gunked too, but can't tell with fluid in it. Someone's hand is in it too .

Also, get a quart of denatured alcohol and use it to flush the lines. The lines will drain themselves with the lines disconnected. After you have the cylinders clean, fill the master with the alcohol. Open the bleed valves and either wait for the alcohol to run out or pump until you get alcohol. Close the bleeders and let it sit, at least overnight. This will let the alcohol work on the gunk in the lines. Then flush.

After the system is clean, you can run fresh brake fluid through. Brake fluid contamination is a bugger to get cleaned, and is the reason why the manufacturers are recommending a flush every year. I think that's overkill, but your brakes must work properly.

[greasemonkey]

Maybe my eyes are crossed, but I think his front reservoir is dry, not the rear. It sounds like Daubs has a lot of air in the front lines if he had to hit the brakes hard enough to lock up the rear drums.

[jacobs]

Originally Posted by greasemonkey

Maybe my eyes are crossed, but I think his front reservoir is dry, not the rear. It sounds like Daubs has a lot of air in the front lines if he had to hit the brakes hard enough to lock up the rear drums.

If I remember right, when GM went to disk brakes they reversed the reservoirs.

[68C15]

actually the forward part of the MC supplies the rear brakes and vice versa.
I agree that a new master and flushed lines anolg with new wheel cylinders is all needed at this time. that gunk in the resivoir looks real bad.

[greasemonkey]

Originally Posted by 68C15

actually the forward part of the MC supplies the rear brakes and vice versa.

Huh? not on my truck.
Line lock is not a good idea for a parking brake, if it's electric. I don't think they are supposed to be activated for more than a short period of time, which is probably why it is kicking off. If you are planning on flushing the system, it would be a good time to take it off if you don't use it.

[Daubs]

Hmmm, interesting annalysis. Wife's doesn't like to drive the K-20 because she said the brakes aren't good. I've just lived with them figuring that a 30+ year old truck is going to have brake issues.

One thing that I do NOT like is the PO installed a "line lock" for a parking brake. It holds the truck for about 30 seconds, then let's her roll. No worries for me because I leave her in low gear when parked. Never had an issue.

I'd like to take the line-lock out. This may be a good opportunity to do that?

You all recommend having this work done? Or doing it myself? Never done new wheel cylinders. But then again I've just finished putting in new crate engine...can wheel cylinders be that hard?

[Fred T]

Lose the line lock.

Wheel cylinders are easy if you buy new or rebuilds at the parts store. I don't know if you can buy them for your truck at the local parts store.

You can rebuild the cylinderrs yourself, but it's not as easy. You need a kit and a hone. If the walls are pitted, I would have them sleeved, your parts store can have that done. If you have to hone too much, the new pistons will leak.

To replace the cylinders, get a good pair of brake spring pliers. After you remove the drum, take a picture of each side, you will need it to put the shoes and springs back in right. The sides are opposite, so unless you can think backward you need the pic of both sides.

[Longhorn Man]

I can't remember which one goes which way, but the 10 and 20 series are opposite in this department. One of them has the front brakes running off the front of the master cylinder, and the other has the front brakes running off the back. I just can't remember which is which.
Line lock is OK to have, just not as a parking brake. Even on a brand new zero mile vehicle, the pressure will bleed down, and the brakes wouldn't be applied anymore.

[70rs/ss]

Originally Posted by Longhorn Man

I can't remember which one goes which way, but the 10 and 20 series are opposite in this department. One of them has the front brakes running off the front of the master cylinder, and the other has the front brakes running off the back. I just can't remember which is which.
Line lock is OK to have, just not as a parking brake. Even on a brand new zero mile vehicle, the pressure will bleed down, and the brakes wouldn't be applied anymore.

On the 10 series the front is the front, on the 20 series it is the the front for the rears and vica versa. I just put a 3/4 ton booster and master, only to have to swap the lines off the cylinder.

[greasemonkey]

I wonder then, seeing he has a K/20, since the front reservoir is dry (rear brakes), they still work; but not the front brakes (rear reservoir) which is full. Weird.
Any update Daubs?

[special-K]

His lines could be swapped by p.o.

[LUV2XCLR8]

Alot of what everyone else already said, but since I worked in a brake shop
for 3 years and this was 1/2 our buisness I would say do these in order

1. Go to Auto parts store and buy 3 large containers of brake fluid
2. Top off resevor and apply pressure to check for leaks or bad MC
3. Fix any leaks and or replace the MC if applicable, if disc check PV
4. Portioning Valves can get stuck causing all kinds of brake issues
5. Fill resevor to the top and put lid on flat and loose, Not tight
6. Open right side Rear* bleeder and bleed till u see new fluid
(Keep an eye on the resevor and refill if it gets low, empty = air)
7. Open left side Rear bleeder and bleed till u see new fluid
(Keep an eye on the resevor and refill if it gets low, empty = air)
8. Open right side Front bleeder and bleed till u see new fluid
(Keep an eye on the resevor and refill if it gets low, empty = air)
9. Open left side Front bleeder and bleed till u see new fluid
(Keep an eye on the resevor and refill if it gets low, empty = air)
10. Top of both resevors and put lid back on tight

*When bleeding always start at the furthest point from the MC 1st

We use 2 peeps at the shop to do this, you should be able to find
someone willing to just sit in there and pump the peddles for ya, &
the reason I said bleed till you see new fluid is this, they did a feild
study a few years back that brake fluid should be flushed every 5
years reguardless of make, model, or manufacturer, but who does?

Disclaimer - I am in no way an expert, these are just basic steps we
used to do brake bleeding, conditions in your area and of your vehicle
may differ from those I encountered during my years of experiance, if
a step was left out I am in no way liable if you crash your vehicle

[Daubs]

Thanks LUV2XCLR8. I haven't done anything to the truck in a few days. Been busy with a few other projects. And still contemplating a carb swap or rebuilding my old Holley 1850.

I had muffler/brake shop check brakes when I had her in for new duals. They said the rear brakes were all gunked up because of the open open holes where parking brake would normally enter (line-lock took place of park brake...).

The pass side rear drum looks like it could be source of the leak. Right now I'm thinking replace the master cylinder and rear wheel cylinders and take out line lock. I'll probably have muffler/brake shop do the work. They will likely have to fab some lines for me in order to get line-lock out.

[Daubs]

Decided I had better get the truck in and have the whole brake system looked over. Took her to the trusty brake/muffler shop I've been using for 20+ years. They tear in to her and find the following:

• left front caliper sticking...inside brake pad worn to nothing
• right front caliper newer, pads seem okay
• left rear drum cylinder/brakes rusted...NO braking power at all from this wheel
• right rear cylinder leaking, no brakes there either
• rear brakes lines really rusty
• neads rear seals

So I'm glad I took her in for the work. Getting new calipers & pads, new master cylinder & rear wheel cylinders, turn rear drums and new shoes back there.

Also taking out the line-lock and replacing some rusted brake lines in rear. I'm guessing the bill will be around $900 when I'm finished. Looking forward to a vehicle that has good stopping power. Can't believe I had only the front brakes all this time. No wonder my stopping distance was so lo-o-o-o-o-o-o-ng.

[Daubs]

Truck is back at home and braking GREAT! Money well spent.

Let's see...new engine, new clutch, new brakes, new carb, new starter, new alternator, pretty new battery. Hmmm, hope the tranny / transfer case doesn't go out soon.

Replacing my truck one part at a time.