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Brake pedal pushes back??????

I have the caddy calipers on the rear of the S-10. I can never get them bled properly, but take it out on the trail and the air bubbles will work their way out.
 
I wish guys. I've got ~3,000 miles on this truck with the same crappy brakes. It's also been to three different shops and several masters. It's also had some pretty abusive offroad adventures, so the damn bubbles should have come up by now.

Where can I get the speed bleeders? Summit?
I'll give them a try.
EDIT: found some on Summit. Anyone know the thread size by any chance? My '85 D60 called for a 10mm x 1.5. I guess I'll have to try the stock one in my rear calipers as I don't know the year they're from.
 
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Sb1015 covers k30&k20 from 76-00, acording to the speed bleeder web page, and you can order them directly from them for $7 each and 5.95 shipping for the whole order
 
At this point, I am leaning away from air, due to the fact that there are no geysers when he releases the pedal.
Plus, unless I am mistaken, we have now achieved a hard pedal with no boost.

I say we, of course, despite the fact I have done nothing other than type on a keyboard........

If I am correct, then all the problems now are being caused by a combination of hard and/or glazed pads and weak clamping force.
I actually think several problems have been fixed.
The push back, was the check valve, and most of the spongy part was the overabundance of rubber lines.

What we need now, is about a 1 inch or so master cylinder instead of the 1-5/16 one on there now.
Despite the possible hard pads, if you clamp almost anything onto the rotors hard enough, its going to stop.

I wish we had a way to measure the actual line pressures, and a chart that gave recommended pressures for given size calipers.

I will look around........
 
Going to grab the stuff from ReadyMix in the next couple mornings. I can get speed bleeders from Summit for $10 a pair and they arrive normally in two days. Fordum linked me to a pressure tester. Thinking about picking it up, at least have or share.

This is all I got at this time :(
 
You can pick up speed bleeders at local parts stores sometimes if you're in a hurry.

I've read the whole thread but still have some questions:
-With where you're at now, are you sure the master isn't bottoming out?
-When sanding are you doing the pads or just the rotors?
-Have you followed the lines all along the frame to see if there are any swollen rubber sections in the middle?
 
When I bleed brakes,I determine when all the air is out by the way the pedal feels and acts--if it feels firm on the first push,and does not "pump up" any higher on the second or third push,then it is bled completely..

I have noticed on later model GM trucks (88 up with the "new" cab style),they decided to run 3/16" lines to the rear brakes as well as the fronts,unlike the older trucks that had a 1/4" line to the rear end,then it splits into two 3/16" lines over the axle tubes..not sure why they did that,or if it makes much difference--I'm thinking maybe since they went to discs in the rear,they need more pressure rather than volume?..:dunno:
 
Like I say, PM me a shipping address, and I will spring for the pressure gauge. Then maybe you can share it around for other folks with problems or doing conversions.

If we attach it to a caliper, and see 700-1200 or so PSI, then it has to be brake pads.
But, if we see 200 or so, like I suspect, then its probably going to be too large a master cylinder.
Remember, a prop valve can only reduce braking force. Of course, that can let the other part of the system have more braking power, but if none of them is good, a prop valve is not going to help.
Its main use is to reduce lockup on a lightly loaded wheel or axle. Not a problem you have thats for sure........
 
Blue85 said:
You can pick up speed bleeders at local parts stores sometimes if you're in a hurry.

I've read the whole thread but still have some questions:
-With where you're at now, are you sure the master isn't bottoming out?
-When sanding are you doing the pads or just the rotors?
-Have you followed the lines all along the frame to see if there are any swollen rubber sections in the middle?
Click to expand...

1) The current MC and booster are off a K30 of the same year. The rod going to the brake pedal hooked up perfectly, no brake light switch adjustment needed. So it should naturally be right for the truck. Having said that, when applying the brakes, the pedal does not go to the floor. When bleeding the brakes, the pedal goes to the floor. That should mean the MC is not bottoming out.

2) I've sanded the discs and pads, very very well.

3) My steel lines along the frame look good. There are no wet spots, dents, or rusty areas. The SS braided drops look good as well. The short rubber lines near the rear calipers also look good. I'd say, just from looking at the system, it's in as good a shape as my 2001 S10.

Thanks for participating in the game :waytogo::doah::haha:

There have been some questions about using a prop valve. This will be my next step before bleeding again. However, I can't see a prop valve ADDING pressure to a braking system.

This is my uneducated guess at how a prop valve works. I have not yet read the link about how brakes work. I will have to sit down and poor over it.

The MC has a dedicated front and rear hole/piston/and reservoir. The prop valve has dedicated front and rear holes. This means fluid is never interchanged, they stay separate. So, fluid exiting the MC will have XXX amount of pressure for the front and XXX amount of pressure exiting for the rear. These pressures never INCREASE. The prop valve only reduced these pressures and throttle them during braking to keep front/rear ratios correct.

So, if the front line coming off the MC produces 100psi of pressure and the rear line produces 100psi of pressure. The prop valve will cut the rear down to 70psi in order to achieve the 70/30 split. It can only do this by feeling the incoming front pressure and regulating the rear. Different trucks need different prop valves according the weight I'm sure. I believe the prop valve also has a check valve in it for safety purposes. If one side looses pressure (ripped brake line) it closes off that side and continues to supply pressure to the other side.

So, running without a prop valve should supply maximum pressure to the front and back. Whatever the the MC is set up for (volume vs pressure) is unregulated. The front will see 100% and the rear will see 100%. This is only a problem if the truck is driven on the street as it can cause the rears to lock up. This is why one of my previous set ups included an adjustable prop valve for the rear. The front was straight line off the MC.

Big giant :dunno: over here though. But please, this isn't so much a discussion or argument. I'm just thinking out loud. I just need the brakes to work :(
 
Here is my opinion.

Put in the prop valve do your best to bleed it.

If it doesn't work load it on you trailer, hope you have one, take it BB14. We will fix it there.

Come out on Wednesday, if we need parts out of SLC or ?? we will have someone bring them Thursday.

Don't give up on the trip because they don't work. There will be enough of us at Moab Rim to rebuild the whole truck if needs be. :waytogo:
 
kgblazerfive said:
Here is my opinion.

Put in the prop valve do your best to bleed it.

If it doesn't work load it on you trailer, hope you have one, take it BB14. We will fix it there.
Click to expand...

I really appreciate that, but I'm trying desperately not to be "that guy" that shows up with a half finished rig. I was planning on trailering it up there anyhow. Just need to rent the trailer and truck, but have been postponing that until I know I can use them. :doah:

I'm tryin' man. Got another friend coming over this weekend. Doesn't know anything but can turn a wrench to help check over all the nuts and bolts. :waytogo: I'll be taking Friday off of work again to get a solid day in. At least all the shops will be open too.
 
I know for myself personally, i LOVE to help my brothers! I would kill for the opportunity to help get your truck dialed in before we went wheeling! Thats the two best things rolled in to one! Add a beer when we're done and im in heaven!
 
That guy is the one that has a half finished rig running it on the trail. If you bring it with brake issues and we know that we can work on it before the trail.
 
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