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1996 f350 7,3 4x4 manual tran.

Having issues with a "spongy pedal" on my son's recently purchased truck. He brought it home and it had the signs of being heavily used, yet solid and runs very well. He noticed his brake pedal went pretty far down before getting pressure. I foolishly mentioned he should probably pick up some shoes for the front and get ready to do a front, then rear brake upgrade as we usually have to on the older rigs that tend to follow young guys home.
After he pulled the fronts apart, he called me over to look at the rotors and to my surprise, they looked almost new. Cool, carry on son everything is looking good.
At that time we also noticed that the master cyl appeared very new also.
Then after he and a friend bled the lines to hopefully gain some pedal height they noticed that it would not hold pressure correctly. Enter halfway mechanic dad. We then preformed the following steps trying to find our trouble.
1st. Re-bled brakes from rear to front. (still mushy)
2nd Removed hose from vacuum pump to make sure it is working. (I have no gauge but it really suks hard on a finger tip)
3rd pulled ling going into power booster and it also is sucking.
4th pulled check valve from booster and it sounded like pulling a beachball plug. (assume that its good)
5th bought new ABS module and installed. Then bled rear pass, rear drvr, front pass, module, then fron drvr side. then bled module again. Still have mushy pedal.

It is better than before, but now the rear brakes lock with an aggressive pedal hit, and the ABS lite is now on??? It has good pedal for a pump or two, then if you keep pressure on it, it will slowly head to the floor.
I am wondering if I should have had battery unconnected during installation of the ABS or if I have improperly bled the system. I do not think for all our effort we have gotten it fully bled.

Any advise would be very well received. Many thanks from Montana.
 

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Mine used to do the same, jacked the rear up and adjusted the rear shoes until they dragged slightly. No more squishy brakes. Also to fully bleed the abs you can accelerate on grass or dirt somewhere and lock them up so the abs acuates. Normally doing that a few times bleeds it
 

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Sounds just like rear shoes out of adjustment, my 95 adjusters were all the way in and I could stand on the brakes and slip the clutch with no throttle input by my foot and the rears would break free on dry pavement. How well does the parking brake work? That's a little bit of an indicator that they are out of adjustment or are worn out.
 

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I believe there is an additional bleed point at the prop valve/abs module, if you didn't bleed that.
 

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Take a look at the front calipers as installed and see if the bleed screws are at the highest point. I know one of my vehicles they were not and this allowed an "air trap" that you couldn't get rid of without re-orienting the calipers so the air could escape through the bleeders. You would need to use something in place of the rotor to ensure the piston doesn't move out when bleeding. Cheers!
 

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I just went through this.. motive power bleeder is a great investment to bleed brakes and not a lot of money. The kit will come with 2 different size o rings since there can be a slight variance in the size of the master cylinder.

You have to narrow things down, and many people change the master thinking it will fix things, and it doesn’t. If the master is good and you bleed the brakes, with the trunk not running you should get a hard pedal. If your hard pedal turns to a soft pedal when running, your booster should be working. Inspect for leaks at every connection, look to make sure lines aren’t leaking from rust anywhere. Make sure the rubber lines are all good and not spongy.

When bleeding you start from the furthest wheel (passenger rear, driver rear, RABS unit mounted on the frame by the transmission) (then passenger front, driver front) and work back to the master. There is a bleed fitting on the RAB unit also. To test is RABS is bad, You can remove the fuse the controls the RABS (google that) or remove the internal spring to check the RABS unit (look on google or YouTube). Either one of those methods should disable the unit. Many people wind up just removing it by connecting the brake lines together. I wouldn’t suggest it, but some people do.

If the master is good, the booster is good, brake lines are good, RABS unit is good, your likely left with only 2 possible causes. Either there is still air trapped in the system (motive power bleeder will make you feel stupid for never buying one) or the rear pads are out of adjustment.

Now here’s the important info - you do NOT need to take anything apart to adjust the rear pads IF, and that’s IF the self adjusters are working correctly. If the rear pads were just done, they SHOULD have been replaced along with all the hardware. The self adjusters can get rusted or gummed up. If you don’t KNOW if they are new, Or working, I’d inspect. If the “drive in reverse method” doesn’t work. If they are working, or really want to test that - all you have to do to adjust the rear pads is drive and stop the truck in reverse.(multiple times) You have to come to a complete stop while doing this (This is important). Find a long driveway, parking lot, dead street and do this. From a stop Reverse - back up, (maybe 5mph 10 at most) hit brakes hard, stop completely. repeat repeat repeat. You can even do reverse - stop, forward, stop, and keep repeating, but the pads only get adjusted while stopping in reverse.

I spent a long time chasing this same issue down (but my truck was not being used) replaced all brake components front and rear, at the same time, and went from a truck that stopped fine to having no brakes.. i bleed , i bleed.. fooled with the RABS unit, changed the master, no luck.. i limped the truck to a nearby parking lot at night, kept driving in reverse and stopping - and went from a truck that was barely drive-able to having perfectly functioning brakes.. must have gone back and forth about 30 times. Pedal slowly got better and harder..

This was on a 1995 f350 7.3 diesel dually with spongy brake pedal (inserted for web search results) Adjusting the brakes that way is what finally did it for me. The RABS unit going seems to be another common issue. Air trapped in the lines another, and for some it really is just a master. The reverse method was passed onto me recently from someone else on another forum that worked on his dodge truck I think. It was actually a service procedure and he posted the pages from the book. This will also be the best way to having your pads adjusted FULLY instead of taking things apart and guessing. As mentioned above - if the parking brake is hooked up, push the pedal down. If it just sinks with no resistance - thats a clear sign they are out of adjustment. You can also save yourself from taking the rear wheels off, by removing the rubber plug in the back of the dust shield and accessing the star wheel of the self adjusters that way. You can turn it with a flat head screwdriver to expand the length of the adjuster. This is unnecessary if you do the reverse, stop method.

Good luck.
 

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I just went through this.. motive power bleeder is a great investment to bleed brakes and not a lot of money. The kit will come with 2 different size o rings since there can be a slight variance in the size of the master cylinder.

You have to narrow things down, and many people change the master thinking it will fix things, and it doesn’t. If the master is good and you bleed the brakes, with the trunk not running you should get a hard pedal. If your hard pedal turns to a soft pedal when running, your booster should be working. Inspect for leaks at every connection, look to make sure lines aren’t leaking from rust anywhere. Make sure the rubber lines are all good and not spongy.

When bleeding you start from the furthest wheel (passenger rear, driver rear, RABS unit mounted on the frame by the transmission) (then passenger front, driver front) and work back to the master. There is a bleed fitting on the RAB unit also. To test is RABS is bad, You can remove the fuse the controls the RABS (google that) or remove the internal spring to check the RABS unit (look on google or YouTube). Either one of those methods should disable the unit. Many people wind up just removing it by connecting the brake lines together. I wouldn’t suggest it, but some people do.

If the master is good, the booster is good, brake lines are good, RABS unit is good, your likely left with only 2 possible causes. Either there is still air trapped in the system (motive power bleeder will make you feel stupid for never buying one) or the rear pads are out of adjustment.

Now here’s the important info - you do NOT need to take anything apart to adjust the rear pads IF, and that’s IF the self adjusters are working correctly. If the rear pads were just done, they SHOULD have been replaced along with all the hardware. The self adjusters can get rusted or gummed up. If you don’t KNOW if they are new, Or working, I’d inspect. If the “drive in reverse method” doesn’t work. If they are working, or really want to test that - all you have to do to adjust the rear pads is drive and stop the truck in reverse.(multiple times) You have to come to a complete stop while doing this (This is important). Find a long driveway, parking lot, dead street and do this. From a stop Reverse - back up, (maybe 5mph 10 at most) hit brakes hard, stop completely. repeat repeat repeat. You can even do reverse - stop, forward, stop, and keep repeating, but the pads only get adjusted while stopping in reverse.

I spent a long time chasing this same issue down (but my truck was not being used) replaced all brake components front and rear, at the same time, and went from a truck that stopped fine to having no brakes.. i bleed , i bleed.. fooled with the RABS unit, changed the master, no luck.. i limped the truck to a nearby parking lot at night, kept driving in reverse and stopping - and went from a truck that was barely drive-able to having perfectly functioning brakes.. must have gone back and forth about 30 times. Pedal slowly got better and harder..

This was on a 1995 f350 7.3 diesel dually with spongy brake pedal (inserted for web search results) Adjusting the brakes that way is what finally did it for me. The RABS unit going seems to be another common issue. Air trapped in the lines another, and for some it really is just a master. The reverse method was passed onto me recently from someone else on another forum that worked on his dodge truck I think. It was actually a service procedure and he posted the pages from the book. This will also be the best way to having your pads adjusted FULLY instead of taking things apart and guessing. As mentioned above - if the parking brake is hooked up, push the pedal down. If it just sinks with no resistance - thats a clear sign they are out of adjustment. You can also save yourself from taking the rear wheels off, by removing the rubber plug in the back of the dust shield and accessing the star wheel of the self adjusters that way. You can turn it with a flat head screwdriver to expand the length of the adjuster. This is unnecessary if you do the reverse, stop method.

Good luck.
Thank you for this good explanation. Everyone needs to read through this when doing their brakes.
 

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Thank you for this good explanation. Everyone needs to read through this when doing their brakes.
It’s not a guarantee this will fix everyone’s problem - but i spent DAYS searching and reading online trying to find out what i was missing. Those are the most common problems people seem to experience. So if you feel like you tried everything else you can think of, try that. The good news is parts are cheap if you search. The RABS unit many not be - which is why many people choose to disable it or bypass it.

I was typing as i was thinking of things, so it may not be in the best order. First thing should prob be to test the parking brake. If they suddenly don’t work, and they use to - chances are its the rear pads needing adjustment. That’s basically isolating JUST the rear pads, and bypassing the hydraulic brake system completely. I had set my new pads that i (thought) i felt slight resistance when i replaced them - BUT - the problem with that is the pads may not be in a perfect circular shape (centered) when you do that. So it might only be a part of one pad making conatct with the inside of the drum initially. When you hit the pedal the first time, the pads try to center themselves and now can be way off..

When doing rear pads (I’m NOT a mechanic) its prob best to put the drums on, hit the brakes with the truck running, and THEN see how it feels as far as adjustment goes. Adjust the star wheels with the drums on, till you get a decent pedal (at least enough to safely drive) and then finish with the ‘drive in reverse’ bit to make sure they adjusted out as much as possible. That should also (in theory) make sure both wheels are adjusted evenly. Check parking brake again.. the idea of the rear adjusters is that they will adjust the rear pads by themselves, under normal driving and backing conditions as the pads wear down. Believe me, i drove myself INSANE trying to hunt this down on my own.

Hopefully someone else more knowledgeable can type up a better step by step than i did.. its been a LONG time since i posted on this forum. The front calibers being installed on the wrong wheels (also mentioned by someone) is another less common problem. The bleeders should be facing up towards the sky, not down toward the ground.

 
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