Need some technical help i.e. I'm stuck (1 Viewer)

Nottajeep

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Last night I convinced my wife to go out and help me after the kids went to bed. We tried the pressure bleeder and pumping the brakes per this thread:


I was surprised that more bubbles came out. The brake pedal felt stiffer, but when I turned on the car you could still get it to touch the floor. I doesn't feel like it is sinking, it feels like it is traveling and then run out of room. It also feels like if I had another inch of travel it would stop.

I'm running out of ideas and I need to take it to someone to fix it for me.
Do you think the booster might be shot?
What happens when you pump brakes?
Does it hold?
 
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Do you think the booster might be shot?
What happens when you pump brakes?
Does it hold?

I have replaced the booster a while ago with a remanufactured one.

I put plugs on the master and when I did that it held pressure great. I think that would mean both the master and booster are good. a leak in either would cause it to fall in that set up.
 

Nottajeep

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I have replaced the booster a while ago with a remanufactured one.

I put plugs on the master and when I did that it held pressure great. I think that would mean both the master and booster are good. a leak in either would cause it to fall in that set up.
What happens when you pump the brakes?
Does it hold pressure?
 
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What happens when you pump the brakes?
Does it hold pressure?
I'm not sure how to describe it. It takes X amount of force to press it down and it will go to the floor, I pump it several times, and it still takes x amount of force to press it to the floor.

With the engine off it doesn't feel like it pumps, it feels like it doesn't pump up, it just goes to the same spot each time.

The x amount of pressure it take to go to the floor is a moderate amount. it doesn't go down easy.
 
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I am starting to think it is the brake booster. When the vacuum is off, the pedal feels solid. When I attach it, is when it feels mush. I drove it today and it has plenty of stopping power.

Last June I bought this boost: 1993 - 1997 Toyota Land Cruiser | FZJ80 | FJ80 *New* Vacuum Brake Booster (Part Number 4461060792) - Wholesale Parts Express - https://www.wholesalepartsexpress.com/product/93-94-95-93-97-toyota-land-cruiser-fzj80-fj80-new-vacuum-brake-booster-part-number-4461060792/ It's made by Mototeknika, which is probably quality. I should probably swap it out for a Seiken 80 Series, NEW OEM Seiken Brake Booster and OEM Gaskets (2), 44610-60792 - http://www.cruiseryard.com/80-series-new-oem-seiken-brake-booster-and-oem-gasket/

I still have my original vacuum booster. I took it off because it lost boosting and the engine was suffering from an obvious vacuum leak. I am trying to remember if I swapped my vacuum line before or at the same time. I think I did swap the line out before the vacuum booster failed. So I think my old one is bad.

Is there a way to test the booster?
 

Godwin

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I am starting to think it is the brake booster. When the vacuum is off, the pedal feels solid. When I attach it, is when it feels mush. I drove it today and it has plenty of stopping power.

Last June I bought this boost: 1993 - 1997 Toyota Land Cruiser | FZJ80 | FJ80 *New* Vacuum Brake Booster (Part Number 4461060792) - Wholesale Parts Express - https://www.wholesalepartsexpress.com/product/93-94-95-93-97-toyota-land-cruiser-fzj80-fj80-new-vacuum-brake-booster-part-number-4461060792/ It's made by Mototeknika, which is probably quality. I should probably swap it out for a Seiken 80 Series, NEW OEM Seiken Brake Booster and OEM Gaskets (2), 44610-60792 - http://www.cruiseryard.com/80-series-new-oem-seiken-brake-booster-and-oem-gasket/

I still have my original vacuum booster. I took it off because it lost boosting and the engine was suffering from an obvious vacuum leak. I am trying to remember if I swapped my vacuum line before or at the same time. I think I did swap the line out before the vacuum booster failed. So I think my old one is bad.

Is there a way to test the booster?

If you decide to go with a new booster this one works and is less $$ Brake Booster for '93 to '97 Land Cruiser FZJ80 FJ80 Lexus LX450 - https://www.cityracerllc.com/collections/land-cruiser-80-series/products/brake-booster-for-93-to-97-land-cruiser-fzj80-fj80-lexus-lx450
 
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Oh that looks attractive. I'm not one for parts snobbery. I just need it to work. They have a great installation guide.

Edit: I have been reading this thread ( New Seiken 44610-60792 brake booster? - https://forum.ih8mud.com/threads/new-seiken-44610-60792-brake-booster.1213795/ ) and it looks like this is a part that needs to be picky about.

Edit 2: Speaking of picky parts. Right now I have a standard vacuum hose, same ID as the original hose. Is it important to get the OEM hose? I am not sure how, given the same length and diameter it should function the same.

80 Series 1FZ Brake Vacuum kit - https://absolute-wits-end.com/80-series-1fz-brake-vacuum-kit/
 
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I think I have it now. I took it to Brakes Plus and Keith let me use his bleeder there. I didn't see any bubbles come out. So I adjusted the pedal up some, by moving the fork out to the end of the push rod coming out of the firewall. Then I adjusted out the plunger going from the brake booster to the master cylinder.

Now when you give it your all the pedal stops just before the floor. It feels "soft" but it stops well. And it can really get it to stop when I stomp on it. It just doesn't feel "tight." I think I am going to live with it the way it is for now.
 

Nottajeep

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I think I have it now. I took it to Brakes Plus and Keith let me use his bleeder there. I didn't see any bubbles come out. So I adjusted the pedal up some, by moving the fork out to the end of the push rod coming out of the firewall. Then I adjusted out the plunger going from the brake booster to the master cylinder.

Now when you give it your all the pedal stops just before the floor. It feels "soft" but it stops well. And it can really get it to stop when I stomp on it. It just doesn't feel "tight." I think I am going to live with it the way it is for now.
Bring it to the next meeting and and see how the other 80s are stopping; maybe someone will let you test drive their rig. I would say that you still have something off.
 
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For those of you keeping score, my bad brakes are winning by 100000000000 points to 2.

In the last 24 hours I took it out for a drive to see how it was doing.

Drive 1: The pedal felt super tight, just touching the pedal caused the LC to stop. It was obviously dragging. The front wheels were hot, there was a strong brake smell.

Drive 2: about an hour later I drove it again, this time down 72 for about 10 minutes. The pedal felt normal. The wheels were cool to the touch, no smell of brakes. Stopped fine. Looked like it was working great. I was so happy.

Drive 3: The next day I went to put gas in it. The pedal felt super tight, just touching the pedal caused the LC to stop. There was pulsation in the brakes. When I turned right there was a vibration. When I got to the gas station there was smoke coming from the front RIGHT brake. The wheel was surprisingly cool to the touch. I drove it home, on a flat road I took my foot off the pedals, and it slowed to a stop. When I got it home, there was smoke coming off the front LEFT, this time.

Drive 4: About 20 minutes after getting home I decided to drive it around the block one more time. This time the pedal felt normal. It drove normal. No pulsation, no vibration. Stopped fine, coasted fine.

The only thing I can think of is that the vacuum boost is engaging weird causing the dragging. Then the next time the vacuum boost is operating normal. So I went ahead and ordered a new Seiken booster from cruiseryard. I hope this does it. I hope by buying a "name brand" part instead of a discount part that I eliminate a variable.

I just want to be able to drive my land cruiser again. 😭
 

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