Topic: mandatory larger master cylender??

[crawlerdan]

i just installed the larger fj rotors, and ifs calipers....and i cannot get it bled correctly, it will push down to about 2 inches from the floor before any resistance is given.


with the motor off, i can pump it and build a little pressure, but with it running, any pressure that i can build, will not hold.


theer are no leaks that i can find


could it just be the need of a larger master cylender?? to help with the increase in volume?

[bigarms23]

When i put bigger rotors on my 4runner i upgraded the mc

[crawlerdan [OP]]

ya i think ill have too

[oddball]

Im pretty sure its the cure Ive read that in several places, actually the description for the larger master that Marlin sells states it will fix the porblem

[*ROKTOY*]

Yep, get the MC master cylinder, no more problem.

[DTB]

From marlins site>>>

"Replacement master cylinder for older Pickup's and 4Runners with smaller bore (bore size is cast into right side of housing). Fits 1979-1995 Pickup/4Runner. Features 1" piston and residual valves for both front and rear. Works with both drum and disc brakes.  Bolt on installation. Includes reservoir. On 1979-1985 Trucks and 4Runners the smaller factory bore works fine with stock, solid front rotors and 8" rear drums. If you upgrade the rear to larger 1986 and up, 10" drums and/or upgrade the front to a vented style caliper you will want to install a 1" bore master cylinder like this one for additional volume.
 
Upgrading your brakes without changing the master cylinder results in excess brake pedal travel. If you have upgraded your brakes on a  1979 to 1985 truck and now you have to push the peddle nearly to the floor, this master cylinder will make the peddle feel like it should."
 

[OOPS]

Are you bleeding the LSPV last?

[crawlerdan [OP]]

well i ordered my MC master cylender today, but my next question is...my rig is an 87, and came from the factory with these calipers and big drums.....so it should be fine.


i want to upgrade the MC anyway, but it should be fine and it certainly isnt

[*ROKTOY*]

well i ordered my MC master cylender today, but my next question is...my rig is an 87, and came from the factory with these calipers and big drums.....so it should be fine.

Wait till you get the new master, bleed it, put it in bleed your brakes and see how it turns out.

[Toymin8r]

You can also upgrade to and FJ80 master cylinder. 

[crawlerdan [OP]]

thats what i ordered

[DTB]

....edit

[RN37DD]

yeah i install the marlin fj80 master cylinder first. no petal travel with the stock brakes. but i had to push harder to lock em up. then i installed the 90's truck ifs calipers and fj60/40 rotors and now have better braking, next phase is to build and install a 90's rear and brakes. what i discovered was even a good master cylinder will not fix old worn out brakes. i removed the load sensing valve. mine was shot. I'll try a good one after the 90's drum's are on.

[crawlerdan [OP]]

i installed the fj MC, all better 8)

[baja2oy]

i have a 85 4runner i did the brake swap with rotors calipers and master cylinder i even got a new booster but i have a problem with my brakes with the truck on or off my pedal i hard it does not go down t all anybody have seen that problem

[crawlerdan [OP]]

i have a 85 4runner i did the brake swap with rotors calipers and master cylinder i even got a new booster but i have a problem with my brakes with the truck on or off my pedal i hard it does not go down t all anybody have seen that problem

sometimes they install a plastic stopper in the master, did you check to see if that was removed???