Pedal still mushy, but better...

[Mark_88]

I ended up bleeding the entire brake system again to see if I may have not done it right the second time...little or no improvement...

I then tried bench bleeding the master, but did it with the master in the truck since I don't have either a bench or a vise, and it seems to be a bit better...the pedal still travels about an inch before it gets serious, but it doesn't go to the floor like it was doing before it would stop...even after bleeding the lines for the third time...

The book (Haynes manual) says to adjust the rear brakes if the pedal is still mushy after all of the above...and I haven't done that as of yet...but just wonding if the master isn't pooched...that would be my next major purchase (and a shorter booster since the current one is in the way of the throttle)...

 

[Guilius]

before you replace the booster entirely, try adjusting the booster pushrod.
you can remove the master cylinder from the booster, and there is a rod, that has two "Adjustable Nut" parts to it.
the first one is to actually adjust the rod in and out (to go deeper into the MC). the second is to hold the rod still because it WILL rotate 360 degrees on you.
i learned the hard way however that the slightest adjustment has HUGE effect on your brakes.

it is worth a shot......

 

[Mark_88]

Thanks for the input...I checked that first...measured the distance from the end of the master to the start of the plunger...and found out they were exact...I didn't want to push it further in in case that caused the brakes to be engaged...because I had that exact problem before and it ended up costing me quite a bit to repair...

Do you know, offhand, if the plunger should be tight against the plunger on the master? The information in my manual shows a special block that you place over the tip to measure the proper adjustment...might try to turn it a notch though...but it is very tight...and hard to get a wrench on the end of that thing...might have to go with vice grips...

 

[Guilius]

yeah it's supposedto be a specific measurement. and you can buy or make the "block" they refer to.....actually cardboard works fine also.

i hadto redo all rotors, calipers ans pads cause i was not aware what the adjustment to it should be either!

as far as tight against the plunger....yes. it should be bareley touching it. this is why i found out later that the slightest adjustment will make such a dramatic change.

the way i made the adjustment however was a set of ignition wrenches. tiny little craftsman wrenches. find the right size and slip the first one on to hold the rod in place, then the second one to make the minor adjustments to the tip.

after my rear axle upgrade (explorer axle w/discs), i had a very soft petal like your talking about. i mean it stopped the vehicle, but it went way down and was soft then grabbed.

after replacing the brakes after our miscalculation, we put it back to the normal spacing and adjusted it 1/16th a turn (we used a micrometer ) out till we got the right brake feel and it has been absoluteley perfect ever since. perfect feel and stiffness to the petal without clamping down with pure brute force like the first accident.

 

[Mark_88]

I tried a combination of adjusting the rear brakes (by backing up fast and hammering the pedal) and adjusted the booster knobby thing...it is actually better...to the point where the brakes engage almost immediately, but I found the pedal would stick some times...perhaps it's from lack of use...or I might have turned it too much...might back it off a bit...

I used a vice grips and channel locks to make the adjustment...I think the 10mm head is kinda worn...probably from the last time I adjusted it about six years ago...

Thanks again for the input...I might back it off just a bit to see...but only after I road test it a bit more to see if the pedal is sticking...

 

[bduke23]

Try adjusting the rear brakes more, it can take quite a lot of backing up and stopping to do a serious adjustment. There should be a rubber plug on the bottom of the backing plate. Pop it out, and spin the starwheel adjuster with a flat screwdriver. Spin it until the pads are just barely contacting the drum when you spin it by hand. It also helps to pull on the ebrake cable from time to time, as this will then center the shoes in the drum.

 

[Mark_88]

Actually, I was avoiding that step because I hate not seeing how much they are adjusted...mostly out of fear generated from previous experience that had the rear brakes locking up on me...but I have been applying the E-brake because it is a standard...

I will try backing it up a few more times and mashing the pedal...if that doesn't work I will try the adjuster directly...everything is brand spanking new on this with the exception of the Aerostar drums...and they were machined (but one actually looks out of round for some reason)...

Thanks again for the input~