2002 F250 power stroke 7.3L diesel turbo - On the way home after buying this beast, I loose the brake pedal. It was solid at the top when I first got in and started it up. So I take the front right wheel off because there was a fluid leak and this is what I find....... the outer pad was half way out of the caliper!



I replaced calipers, brackets, disks and pads......



I have been through the bleeding process and here are the results.....
1. some air and then a small "dribble" of fluid from both front
2. no air and great flow from both rear
3. removed lines from calipers and only a dribble of fluid on both fronts
4. pedal goes all the way to the floor and creates a "noise" in the engine compartment like the PS pump is low on fluid
5. can not get pedal pressure
6. filled the PS reservoir but found it empty after bleeding process
7. found hose from master cylinder to PS pump.. Is the fluid from PS to MC the same?
8. I have been using brake fluid in Master Cylinder and power steering fluid in PS pump
9. I found that I should be using ATF in the PS unit
10. Should I be using ATF in the master cylinder?
11. Is there a "modual" of some sort in the brake system that requires bleeding via access to the computer?

My first diesel and first 4 wheel disc.... I am getting a real edumacation on this one.... HELP!

 

You probably had air enter from the master cylinder reservoir into the brake lines as you bled. Perform a full flush with a pressure bleeder like this one: Motive Products 0090 Power Bleeder Tank
The advantage of using a pressure bleeder is that you can fill the bleeder with a lot of brake fluid and then you don't have to worry about running the reservoir dry.

Our trucks use hydroboost for brake assist and that uses hydraulic pressure from the PS pump. The fluid used in there is ATF. Do NOT use conventional power steering fluid. A lot more stuff to talk about but I have work to do. I'll be back if others haven't chimed in by then.

 

10. Should I be using ATF in the master cylinder?

Never, ever. Only DOT3/4 brake fluid. The only place ATF goes is in the power steering pump reservoir.

 

Great information! I have done many brake system bleeds so I am careful regarding the master cylinder fluid level. I checked it after every wheel and it never got less than 3/4 full. I am very doubtful that any air entered through the MC.

I have added PS fluid in the PS pump but I will do a flush on it with ATF, Perhaps I have a PS system leak.... could that contribute to the "no pedal" condition.

As far as the response is concerned, I won't be in a panic until the first snow flakes so I'm good for the moment.

Thanks again.

 

I figured but the hose from the PS pump to the Master Cylinder really confused me. THANKS!!!

 

Did the master go empty at any point while you were doing the work? If so the master needs to be "bench bled" before you even bother bleeding at the calipers.

 

No it did not. Thanks

And just for reference, what is "bench bleed"? I assume it means taking it off the vehicle and completely emptying it.

 

So I decided I needed to check all the lines including the power steering pump for leaks. I took out the battery, the air intake parts and the turbo "tube" so I could see everything. In the process I found what I think is a connector block for the positive battery cable going to the starter. When I tried to move the cable, it broke off. What is this part called and can I get a replacement and the connectors that go on the end of each cable?

 

The power steering pump looks good as far as any leaks go. Does the PS fluid go to the power booster at the master cylinder? There is also a "modual" where the brake lines go in and out. Does this require bleeding?

thanks

 

Hmmm, my truck doesn't have that terminal block for the starter's power supply. My starter has a cable going direct from the passenger side battery clamp to the starter. Can you take a wier angle shot of that terminal block to show where it is normally situated?
That booster with PS fluid going to it is the HydroBoost I was telling you about.
That's the ABS module with all the brake lines going in and out. Unless brake hydraulics completely ran dry, you don't normally have to bleed that. It wouldn't hurt though.

 

Only certain years had that terminal block that sits on the driver side fender. I cannot recall if there is a direct replacement for it, but it obviously needs to be reconnected before running the truck.

As for the ABS module which is the piece behind the driver side headlight, @dmueller71 just went through this. He found some instructions online which I believe he plans to post here soon and he took some video of the process.

I hope to include both the instructions he found and his video in the 7.3L PSD Tech Folder soon.

 

Hope this helps......

 

Here is a pic of the location of that positive battery cable junction block and the broken cable. I put the probes from my multi meter on the ends of the broken cable. I'm thinking that if I can't find terminals I'll just "rig" something up to make a good solid splice of the wire.

I filled the PS pump and let it sit for the last couple of days and the level did not change. Of course that's not under pressure but it's a good sign.

I'm still having trouble identifying the power booster. I see where the hose goes from the PS pump up to the MC. Does the PS fluid go into the MC and then to the power booster somewhere on the other side of the firewall. Like inside, under the dash? I've seen diagrams where the power booster operates on a vacuum but I don't think my is like that.

If I fill the MC with brake fluid and disconnect the 2 lines at the "block" behind the headlight, can I then bleed the MC that way instead of removing it from the vehicle?

thanks


Broken positive battery cable

Black and red probes pointing to the ends of the broken cable

Behind the MC left

Behind the MC right

Behind the MC top

Hose from the PS pump to the MC

PS pump and hose to MC

 

One thing I keep forgetting to mention is that I have great flow on both rear brakes. No air and the stream squirts out about 2 inches! On the other hand all I get is a dribble on each of the fronts. I disconnected the line from the caliper and let it sit for several hours and it drained half the MC reservoir. Blocked lines both sides front?

 

Had the same brake caliper piston lock 'out' as you did 3 times on the back drivers side... One totally destroyed and two stuck out. not very good for fuel mileage.

The solution to fix 'my' issue after talking to a few people was to replace all of the rubber brake lines. After 18 years the lines have degraded to much on the inside the debris was hindering the flow of fluid 'out' of the brake cylinders and keeping the brakes engaged. I also replace a couple of metal lines. I blew the remaining metal lines out to make sure that no debris was in them. As you know the brake fluid will 'peel paint', careful when blowing out lines. My jack stands are now very 'spotted' in colors.

There is a reason the calipers are sticking (out). Your slide pins may have not been cleaned and greased as often as they should have.