Brakes.......Or Lack There Of
- Thread starter '94IDITurbo7.3
- Start date
'94IDITurbo7.3
HAMMER DOWN!
i checked the booster pushrod length and it is good.
is there anyway to tell if the front callipers are bypassing inside?
is there anyway to tell if the front callipers are bypassing inside?
redmondjp
Full Access Member
This can't happen - if the piston seals leak, you will eventually see fluid leaking out (the dust boot will contain a little, but it will not hold any pressure).
Did you ever get all of the air out of the master cylinder?
'94IDITurbo7.3
HAMMER DOWN!
i didn't touch the brakes this weekend. i guess this wednesday i will try gravity bleeding.
redmondjp
Full Access Member
i didn't touch the brakes this weekend. i guess this wednesday i will try gravity bleeding.
Well, now that you have the master cylinder installed on the vehicle, you can sit in the truck and cycle the pedal up and down - this will slowly bleed some of the air out (if you are still seeing air bubble up inside the reservoir - do this until no more bubbled appear).
Then, to finish bleeding the master cylinder, have a helper press down on the pedal while you crack open the brake line fittings (one at a time) right at the master cylinder, and then tighten the fitting before the helper releases the pedal. This is MUCH faster than trying to force that air all of the way through the system, and more effective, as the air wants to stay at the highest point in the system anyways.
'94IDITurbo7.3
HAMMER DOWN!
so for this will i take the cap off the mc while i pump the pedal?
riotwarrior
Full Access Member
This method will quite literally kick ass over gravity or worse...Vacuum bleeding where cups can be pulled inwards drawing in air past the cups (though likely not happening in most situations)
I'll be making one of these and purchasing a few caps for this method or making adaptive plates of sorts that will work for those old Iron dual chamber MCs.
This unit will actually also work well for clutch slave bleeding too I believe
making short work of that...so another adapter 101 to fab up...From a pressure test that held sufficient pressure on the MC, then the only conceivable thing left is a wheel cyl or caliper that is awry. By that if a rear wheel cyl is working correctly but somehow the brake shoes are not fastened on the bottom but in the groove of the pins on the cyl with the return springs pulling back then the wheel cyl...could conceivably move more because the bottom of the shoes are not aligned correctly...just some speculation here...this is puzzling...NOW
One more thing, and it's ******* me off
that I cannot remember where on the net I read it. There is a TSB about this and how the MC is incorrectly sized. It will not provide enough volume to make the brakes function. It is a little known issue but there is a TSB about it. I cannot recall what year it was or where but this could be an issue that your hitting.How about checking that MC piston size...then see if that's the correct one or if there is a recommended replacement of greater size?
JM2CW
redmondjp
Full Access Member
It's not absolutely necessary but does make it easier to see if bubbles are coming out, and also makes it easier to add fluid.
'94IDITurbo7.3
HAMMER DOWN!
i will check for the TSB tomorrow at school.
is there any way to check the size of the mc other than drain the thing and take it apart?
is there any way to check the size of the mc other than drain the thing and take it apart?
'94IDITurbo7.3
HAMMER DOWN!
i guess it would make it easier to add fuid.
i think i am going to make that pressure bleeder.
riotwarrior
Full Access Member
Size is usually on side of MC cast in large #'s opposite the LINES near the flange to bolt to booster FYI
or at least all the ones I got kickin round here are...as follows
89 F350 CC 4x4 351 5sp MC 1 1/8" MC
89 FSuperduty 460 5sp duals hydro assist disk rear 1 5/16" MC
03 F350 SD diesel St hydro assist 1 5/8" MC
All marked in same location easy to read. I am upgrading my stock Bronco from what ever it was...to the 89 Hydro assist and later when the diesel gets swapped in the 03 SD Hydro with custom lines...
riotwarrior
Full Access Member
I hope u can find the TSB...
Also let us know your MC size and by chance others can chime in with theirs...this may help to solve the issue too...too small a MC size will not displace enough fluid to move the calipers and shoes....before you run out of volume making pedal travel way to far!
'94IDITurbo7.3
HAMMER DOWN!
we have alldata and mitchell at school. i should be able to find something.
will do on the mc size.
will do on the mc size.
riotwarrior
Full Access Member
Must be nice, I could sure use that ....
FYI I just checked my 89 F250 2x diesel EC LB 5sp and it has 1 1/8" bore MC too...
gingrass179
Full Access Member
honestly when i got my truck i had the same issue went with it for about a month just dumping parts was super frustrated went to adjust the rear shoes 1 more time and noticed my adjuster star was backwards it has to go a certain way so it can spin out but not back down and make sure the thin metal piece pushing on the gear has good tension solved my issue!!!
