Brake mystery in a HJ60-long, but need advice! (1 Viewer)

[dieselDaryl]

Hmm.. Mine was a 'new' master Clyinder (Alstrom P9885 posted elsewhere in the forums)

I've heard of people needing to try several master cylinders. Maybe I will go for OEM ($220) or so... But I will check the booster operation first. I've done all of the tests in the manual.. ie pedal sinks when I start the truck, etc...

Glad to hear that your issue is resolved..

So here’s the latest update:

I removed the Alstrom MC(P9885) and installed a new Raybestos one (MC39996)

The brakes haven’t gotten any better. They are still ‘okay.’ I adjusted the booster and bled the brakes once again. I also bench bled the MC before putting it on.

The strange thing is the pedal will ‘bottom out’ with a moderate amount of pressure. Either stopped or while moving. It is definitely a metal on metal type contact, like the end of piston travel. Is this normal on an HJ61? I don’t remember that from before.

I’m still thinking there is air somewhere but I’ve bled the system repeatedly. How important is it for the vehicle to be perfectly level to bleed? My suspension in the front is slightly lower than the rear and I thought maybe somehow that’s affecting the bleed process.

Grasping at straws here..

Daryl

P.S. Both of these master cylinders were a direct bold up (reservoir, brake lines matched up exactly) but the factory unit I originally removed was a 7/8” bore and these were both 1” bore. Lordco said the MC39996 is spec’d for an 89 Toyota 4x4 V6 Pickup.

 

[Tapage]

I’m still thinking there is air somewhere but I’ve bled the system repeatedly. How important is it for the vehicle to be perfectly level to bleed?

I thought isn't important ..

 

[Jan-78FJ40]

I agree with David, the angle is not important for the bleeding.
Otherwise I am not much help...
jan

 

[dieselDaryl]

I agree with David, the angle is not important for the bleeding.
Otherwise I am not much help...
jan

Jan,

Can you comment on the brake pedal issue? Right now in my truck, at idle or while driving, I can mash on the medal until it hits a hard 'end point' where it reaches what feels like the end of its travel. I don't rememebr this always being the case.. When the brake system was healthy, I seem to recall the pedal going down but reaching a point where it is firm and would take a lot more pressure to move it. RIght now it feels that I probably could push the pedal further but it has reached its limit of travel. I don't know if this is due to the MC being 1" bore versus 7/8. Maybe it's the wrong aplication even if it does bolt up.

I'm going to try bench bleeding my old MC and installing that again.

I'm also going to see if I can drive another HJ61 to determine what is 'normal'

 

[Jan-78FJ40]

Jan,

Can you comment on the brake pedal issue? Right now in my truck, at idle or while driving, I can mash on the medal until it hits a hard 'end point' where it reaches what feels like the end of its travel. I don't rememebr this always being the case.. When the brake system was healthy, I seem to recall the pedal going down but reaching a point where it is firm and would take a lot more pressure to move it. RIght now it feels that I probably could push the pedal further but it has reached its limit of travel. I don't know if this is due to the MC being 1" bore versus 7/8. Maybe it's the wrong aplication even if it does bolt up.

I'm going to try bench bleeding my old MC and installing that again.

I'm also going to see if I can drive another HJ61 to determine what is 'normal'

Your pedal should definitely reach a firm point soon. If you can depress it too far, it means you are loosing pressure somewhere.
If you do not have a leak anywhere, and no air in the line, the only way to loose pressure is in the MC, as far as I know.
A larger bore would mean a larger amount of liquid being pushed into the brake lines, so the pedal should reach a firm point faster, not after more travel.
I don't know if any of that helps. If in doubt, I would put on the exact MC for your truack, and only a new toyota part (no remanufactured one).
Jan

 

[Jan-78FJ40]

I am pulling this thread to the front, since I solved the brake problem I had this weekend.
Even after putting on a new master, the pedal still did not feel right, and would engage the brakes after varying pedal-travel distance.
So I pulled the tires and calipers this WE, and found that the wheel bearings were too loose. There was about a millimeter of wiggling room on each wheel, enough for thebrake discs to push in the engaging rods of the calipers, resulting in longer brake pedal travel till they are pushed out again.
This is a result from me rebuilding the wheels without a hub socket-no snide comments on that error please.
anyway, I checked the bearings and races, and they were fine. so I put it together correctly, torqued it correctly, and now it has the correct preload.
As a result the brakes are firm and work great, consistently.

So, to finish up the thread, my problems were due to a bad master, and loose wheelbearings.
If anyone is suffering from unexplained fading of the pedal, without a leak or air in the lines, this is something to consider.
thanks,
Jan

 

[crushers]

congrates on the solution, now go buy a proper socket..
;^)