Disc break conversion problems

Joined
Jun 29, 2021
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9
Location
Oregon City, Oregon
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I bought my FJ40 about three weeks ago knowing it had some break issues. PO said parking break cable and drum were the issue with it not being drivable. Locking up after 200 feet.

I rebuilt parking break and attached new cable (previous cable was broke). Realized this is not the problem after talking with land cruiser specialties….

Tim said sounds like break booster, break master cylinder might be out of adjustment. I raised front and rear end found all four wheels “tight” from breaks.

I adjusted break booster rod all the way in. It’s alive! Traveling now in the neighborhood. But not 100%.

No more room on break booster rod to shorten the throw.

Question? Do I cut the length of break booster rod to have more clearance? Aka room for throw?

am I missing something?

Aisin break master cylinder. Assumed stock break booster.

4D4A748C-BF77-4045-BC78-4A34620EBB2C.jpeg
 

3_puppies

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Dec 2, 2002
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15,332
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Helena MT
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4 wheel disc brakes?

the booster adjustment is between the booster and the master, if the booster is applying slight preasure to the master, the brakes will lock up eventually
 
Joined
Jul 9, 2021
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15
Location
Blairsville GA
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I bought my FJ40 about three weeks ago knowing it had some break issues. PO said parking break cable and drum were the issue with it not being drivable. Locking up after 200 feet.

I rebuilt parking break and attached new cable (previous cable was broke). Realized this is not the problem after talking with land cruiser specialties….

Tim said sounds like break booster, break master cylinder might be out of adjustment. I raised front and rear end found all four wheels “tight” from breaks.

I adjusted break booster rod all the way in. It’s alive! Traveling now in the neighborhood. But not 100%.

No more room on break booster rod to shorten the throw.

Question? Do I cut the length of break booster rod to have more clearance? Aka room for throw?

am I missing something?

Aisin break master cylinder. Assumed stock break booster.

View attachment 2720325
I had the same problem with mine. Had to adjust the pin all the way in and also back out the clevis that attaches to the brake pedal arm all the way back until the rod hits the arm. Also had to remove the residual valve from the master cylinder. Looks like a thimble with a little hole in it. Used the grease test on the booster rod to check its depth. Place a little grease on the end of the rod, mount the master cylinder back to the booster and take it apart again. The grease should remain on the end of the rod.

Residual Valve 1.JPG


Residual Valve 2.JPG
 

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