Ford F150 1998 4.2L Master Cylinder going?

I would look at each cylinder/piston for brake fluid leaks first, then lines and master cylinder. If no obvious leak spots are found, purge the brake fluid.

A soft pedal indicates air in the system, and brake fluid is hygroscopic so moisture increases, which will cause various sometimes expensive problems. This is worse just sitting, as there is no heat to drive out moisture.

When you do your full bleed, dark or discolored brake fluid will confirm that it was overdue for a purge after sitting

Thanks for the comments.

When the drivers rear wheel cylinder went, the brake feedline to it ruptured, and they custom made a new one from the "Tee" fitting on the axle, which they said is a relief pressure valve, is theres too much pressure thats suppose to activate I guess.

So when I was driving with the ruptured line, lost of fluid escaped, had to fill the master with fluid 2 times, so its more or less had a fluid flush n fill.

At some point he said there was still some air trapped in the system and if I drove and hit a sharp bump that could force the bubble back up into the master cylinder and act like a bleeding.

When the wheel cylinders were changed the shoes on that side had some fluid on them and they said good idea to change them or they can shoot them with brake clean and hope for the best so I had them do that rather than a new set of shoes.

One day there was smoke coming out of that wheel, it was some fluid burning off the shoes so took it back for a check to the same shop, he said the shoes were stuck to the drum on that side. His boss would not let him put it on the lift and open that side unless I paid a fee upfront, so he looked at it in the parking lot.

He took a hammer and screwdriver and went under that side and banged it a few times and had me try the pedal again and it came back up and has been fixed since.

He also may have knocked an air bubble out of that side, as a different mechanic did the cylinder job out of state.

I would still do a full brake fluid purge on any vehicle which was parked for that long an interval.

Good advice from Amuzi. To add to that, if you plan on keeping the truck then replace all the steel lines, either rebuild all wheel cylinders/calipers or get rebuilt ones, the master cyl seals are likely leaking. Possibly leaking into the vacuum booster and rotting that out, too. I've seen the brake pedal slowly going down if the brake booster is leaking vacuum internally. Check the one way vac valve, too. I bet you will find the mstr cyl and all wheel cyls full of rust if you take them apart. Replace them along with the steel lines. Rock Auto has everything you need including new steel lines.

Update

Last night the ABS and Brake light came on. Checked the fluid and was very low, topped it off , lights are gone but I can see the brake line from the master to that side caliper is leaking fluid and its dripped onto the frame.

Hopefully just a brake line....might have all the front ones done to get it over with.

The advice from Paul in Houston was correct.

Any vehicle sitting 12 years has absorbed moisture into the brake fluid; new lines rebuild or replace cylinders is the right path.

And not all that expensive compared to cruising through a red light...

Flushing the fluid completely from all lines is the first step, and that includes the clutch lines if you have a hydraulic clutch. This prevents further damage from being done.

THEN it's time to start seeeing what is failing and I would be very surprised if you don't have bad brake lines at all of the lowest points in the system and if your master cylinder doesn't have bad seals.

You can rebuild the master cylinder yourself with a seal kit but it isn't that much cheaper than getting a quality rebuild.

--scott

Good link, I bookmarked it.

Noticed they dont list the isolator bolts for the intake manifold.

There dont seem to be a way to contact them for research to include them.

Also I now need the dipstick filler tube as the mounting ear bracket rusted off.

Started a thread on it here:

Transmission 4R70W 4R70E Fluid Filler Dipstick F75Z-7A228-DB O ring 391308-S But thats the dipstick, not the filler tube part No.

It seems like people say its a good idea to get the oring, so that part number is probably correct. I believe my VIN decodes to that 4R70W auto trans? So how to find the filler tube part no?

Also no listing for it on Rock auto...?