WHOA...... or lack of....

[Hotweels]

just finished up the driveline end of my D44-9" swap and took my new toy for a short trip down the back alley... i am having some issues with my brake system....

hard lines... all new lines on front and rear diff
soft lines... OEM rubber from knuckles out
drop lines.... skyjacker SS front and rear 78 bronco
new master cylinder
bypassed RABS valve
new calipers front
75% shoes ford 9" rear no leaks everything look's pretty new
bled about 1/2gal of fluid thru the system

pedal is soft and wont get very stiff with the engine off even after pumping 20-30 times
turn engine on and pedal goes to floor with little effort

any ideas?
will poorley adjusted rear shoes cause this problem? i set them up with a little bit of drag but nothing too aggresive..... my last guess will be the drum's are shot... i dident have them checked

 

[Howard]

One means of helping to diagnose the problem is to crank up the adjusters on the rear so they lock the wheels. Then try the pedal. If is now hard then the problem is in the rear. If it is still soft then the problem is in the front. Hope that helps a bit. Also when adjusting drum brakes I always lock up and then back off till just free. This ensures that the shoes are centralised in the drum.

You can also use clamps on the flexible pipes to eliminate areas of the system. Could just be a faulty master cylinder.

 

[Creager]

One means of helping to diagnose the problem is to crank up the adjusters on the rear so they lock the wheels. Then try the pedal. If is now hard then the problem is in the rear. If it is still soft then the problem is in the front. Hope that helps a bit. Also when adjusting drum brakes I always lock up and then back off till just free. This ensures that the shoes are centralised in the drum.

You can also use clamps on the flexible pipes to eliminate areas of the system. Could just be a faulty master cylinder.

I like his idea. Adjust them to where you have to hammer the drums on, and see if the problem is still there..

New calipers? Check the bleeder valves... the new calipers i bought from autozone weren't cast right, and the bleeder valve wouldnt screw in all the way, causing a very slight pressure leak...

do you have any RABS/BOO lights?

 

[410Fortune]

Dont forget your stockish master cylinder does not have the capacity to handle the larger front calipers, in theory anyways. This is likely not your problem because even with this you should have a firm pedal but I do recommend using the master cylinder from a full size Ford for better performance....

 

[Hotweels]

hmmmmm well it would not be the first time i got a faulty new part but my OEM master i just replaced was still pretty good and i had the same ammount of pressure i just replaced it for peace of mind

Creager
yes with no tone ring in the rear diff and the sender unit taped and tied to the frame rail plus a bypassed RABS valve my rear antilock light is lit up.... till i get the energy to remove the bulb.
you dont have to pre-adjust rear shoes before u put the drum's on there is a lil slot that can access the adjuster with a brake tool or even driving in reverse and hitting the brakes works some times.

410
i see yer point with the stock MC not being able to handle the bigger front calipers but out of countless SFA threads i have read the MC is never brought up so i never thought it to be an issue.


going to go re-cross all my T's and dot all my i's just to see if i messed up somewhere.

 

[Hotweels]

heh..... the parts guys love me....

pulled my rear drum's off today and took them down to the parts store and asked em to throw the gauge in em.... they where shot... also the lil cable that holds the adjuster up was broken on one side so it was not adjusting properly....

nothing sounds quite like a big 12.5 wide mud tire going from 20kph to 0 locked up solid.... times that by 4 and it's ummmm 4x as cool