Brake problems, need advice

[BLACKDOG]

Just finished up the swap to 1 tons.  For my brakes, I've got OEM Ford drums on the rear, OEM GM disks up front, a GM 1 ton M/C, and the toy booster.  I can bleed the lines all day long, but I to develop pedal pressure, I've got to pump the pedal.  It does stop the truck, but not real well, and the pedal goes to the floor. 

I did not bench bleed the M/C (didn't even think about it) before I put it in?  Could this be the problem? 

My bleed process is as follows
Drivers front
Pass. front
LSPV
Driver rear
Pass. rear

Problem there? 

Any other suggestions?

[Steve_925]

are your rear brakes even working? leaky booster?

[BLACKDOG]

are your rear brakes even working? leaky booster?

Not positive on the rear brakes.  I would assume so, but I dunno.  just pulled in one end of my driveway and out the other, didn't want to spend much time on the street with it.

Booster worked fine before I did the swap, no indicators that its bad now

[Steve_925]

i would lift the rear tires off the ground and see if the brakes work. it might be the prop valve

[Cheesemaker]

#1 rule, always bench bleed the master.   

[BLACKDOG]

So, seeing as the master is now in the truck, is there a way to "bench bleed" it without pulling it out?

i would lift the rear tires off the ground and see if the brakes work. it might be the prop valve

I'll give that a shot tommorow. 

[79coyotefrg]

pull the lines off and have someone push the pedal down as you hold a finger over the ports in the master, after you start getting nothing but fluid then reconnect the lines and bleed the system using the "buddy system"  ie, have buddy push the pedal and you crack the bleeder ONLY under pressure, then close the bleeder BEFORE buddy lets off the pedal


then you need to adjust the rear brakes up till they give you some drag on the drum

[bigarms23]

when i did mine i blead mine driver rear, pass, pass front and last drivers front. i had to bleed mine 5 times before my brakes would work properly

[basser530]

full the lines off and have someone push the pedal down as you hold a finger over the ports in the master, after you start getting nothing but fluid then reconnect the lines and bleed the system using the "buddy system"  ie, have buddy push the pedal and you crack the bleeder ONLY under pressure, then close the bleeder BEFORE buddy lets off the pedal


then you need to adjust the rear brakes up till they give you some drag on the drum

X2 

[BLACKDOG]

full the lines off and have someone push the pedal down as you hold a finger over the ports in the master, after you start getting nothing but fluid then reconnect the lines and bleed the system using the "buddy system"  ie, have buddy push the pedal and you crack the bleeder ONLY under pressure, then close the bleeder BEFORE buddy lets off the pedal


then you need to adjust the rear brakes up till they give you some drag on the drum

do you mean nothing but fluid against my fingers in the ports?  Or no more air bubbles in the system?


That is how I bleed my brakes, so good there



Thanks guys!

[basser530]

Solid fluid from the ports then bleed the rest of the system again starting from the farthest point from the M/C and work your way up.

[79coyotefrg]

do you mean nothing but fluid against my fingers in the ports?  Or no more air bubbles in the system?

nothing but fluid from the MC ports, THEN  bleed the rest of the system

[brainlessfool]

and make sure the rears are ajdusted up. realy. should be  snug if the tires are on.

[BLACKDOG]

Messed with it some more.  I may need to take the drum off one side.  I think the brake springs popped loose or something.  Not sure. 


I put the rear end on jack stands, spun the wheels, and hit the brakes.  It took a while for them to work.  I tightened up the shoes a bit, and did the same thing again.  Got better results, but I still had to pump the brakes

I did attempt to bleed the M/C, then the rest of the brake system, farthest point first and working my way to the M/c. 

When the truck is not running, I get good pedal pressure.  When I start it, that is when the pedal gets spongey, goes the the floor, and needs to be pumped for them to work.

[79coyotefrg]

you may need a new booster,  if the diaphram is bad the vacuum could suck fluid (in theory)

[Steve_925]

or the booster just isnt strong enough for the 1 ton master

[Snowtoy]

Just finished up the swap to 1 tons.  For my brakes, I've got OEM Ford drums on the rear, OEM GM disks up front, a GM 1 ton M/C, and the toy booster.  I can bleed the lines all day long, but I to develop pedal pressure, I've got to pump the pedal.  It does stop the truck, but not real well, and the pedal goes to the floor. 

I did not bench bleed the M/C (didn't even think about it) before I put it in?  Could this be the problem? 

My bleed process is as follows
Drivers front
Pass. front
LSPV
Driver rear
Pass. rear

Problem there? 

Any other suggestions?

Your bleed order is backwards compared to stock.
Stock bleed process
Driver Rear
Passenger Rear
LSPV
Passenger Front
Driver Front

Are you using a one man or two man bleeding system?

[basser530]

or the booster just isn't strong enough for the 1 ton master

I'm running a 1 ton M/C with my stock 4runner booster and my peddle is as hard as a rock. Especially after I adjusted my rear drums. I'm not running 1 tons but I am running a 44 and a 12 bolt. Chevy M/C conversion is the best thing I ever did for my braking system. 

[BLACKDOG]

Your bleed order is backwards compared to stock.
Stock bleed process
Driver Rear
Passenger Rear
LSPV
Passenger Front
Driver Front

Are you using a one man or two man bleeding system?

  yup, I realized that, and I'm using a 2 man system.


Replaced the M/C, world of difference.  Also opened up a drum, and discovered a broken adjuster screw, and fixed that.  The brakes are working now, for the most part.  did a good bleed on the system, in the correct order.  Got good fluid, no bubbles, etc.  The M/C was also bench bled until no bubbles came out.   I'm going to play with it a little more tommorow, but still now, the pedal goes almost all the way to the floor on the first push, unless I've just ramped up the RPMs.  If I've just done that, or do that simultaneously, brake pedal is solid, and the truck stops well.  I'm wondering if my vaccum line is bad, I've got an extra, going to try that, and adjusting the drum shoes a little tighter.

[Cheesemaker]

If you found a broken part in the brakes, I'd do a complete rebuild on the rears.  The parts are cheap and easy to do.  That way, you don't have issues coming off a steep descent.  

I'd definitely look into a new booster.  And look for a leak.  Sounds like a low vacuum issue if you have no leaks in any lines.  Might have to look into a vacuum canister to help with lost vacuum.   

[H8PVMNT]

Bloody bleeding brakes!  My buddies 4runner had the same problem.  Turned out that it had peices missing from one of the rear drums.