Brake Booster Adjustment (push rod) (1 Viewer)

[toyofan]

Hi !

I need to replace my brake booster, and the procedure seems fairly simple.

However, I am not sure about the push rod adjustment. Is that something I need to worry too much about ??? (even if I get an OEM booster), and if so, how do you guys adjust it without the SST ?

I searched and could not find anything on this. Thanks !!!

 

[toyofan]

Please help



...via IH8MUD app

 

[Summiteer]

Curious about this too as I'm getting ready to change one out.

 

[unklwedy]

Shoot for very small clearance(but not zero), say 0.001-0.003" between push rod and brake master. A bit of ABC gum can be used as gage.

 

[elhombre]

Haven't done it myself, but a while back someone said use old style carbon paper. The stuff you would put between two sheets of paper and write on the top one. Then the carbon paper would transfer what is being written on the first, down to the second. Here ya go http://www.staples.com/Staples-Carbon-Paper-8-1-2-inch-x-11-inch-Black/product_150912.

You take a small piece and place it inside the master cylinder, extend the push rod further than necessary so it is too long. Bolt the master onto the booster. Remove. Look at paper, it should show a mark from the end of the pushrod. Take some length out of the pushrod. Repeat, until the tracing paper no longer has the pushrod leaving a mark or you don't see a black spot on the end of the pushrod any more. Sounds like a good idea, but like I said .......

 

[Buckru]

I laid a ruler across the top of the booster over the pushrod of the old unit and measured. Matched up the distance on the new. Gravy

 

[toyofan]

great suggestions guys !!!...i"ll be working on this Saturday THANKS !

 

[Dennis 1970 40]

Longtime issue with me on poor brakes. The booster was replaced when the FJ40 was out of my care years ago and brakes are now terrible. I realized that the push-rod (pin) was never adjusted between the new booster and the MC... I have adjusted 3/4" inch and now the brakes are working at about 70%... It has occurred to me that the Booster was the wrong item or the pin is now the wrong length. I'm seriously thinking of replacing the booster again but this time using a vendor with knowledge.
1. Any suggestions on the push-rod being adjusted so much vs original length?
2. Suggestion on a vendor with the correct booster for this FJ40 including the correct push-rod pin?
3. September 1970 FJ40
Thanks for any help.

 

[Red Merle]

Longtime issue with me on poor brakes. The booster was replaced when the FJ40 was out of my care years ago and brakes are now terrible. I realized that the push-rod (pin) was never adjusted between the new booster and the MC... I have adjusted 3/4" inch and now the brakes are working at about 70%... It has occurred to me that the Booster was the wrong item or the pin is now the wrong length. I'm seriously thinking of replacing the booster again but this time using a vendor with knowledge.
1. Any suggestions on the push-rod being adjusted so much vs original length?
2. Suggestion on a vendor with the correct booster for this FJ40 including the correct push-rod pin?
3. September 1970 FJ40
Thanks for any help.

Honestly, this is one of the trickiest things I have ever fiddled with on an 80. There is no good way to measure the depth with normal gauges and the push rod moves in and out and it's extremely frustrating to try to get it to mate with the MC right. That said, 3/4" might as well be a mile. It will be very, very close to the factory settings, but if you lose those by adjusting it, good luck. I ended up just getting a different booster that was already set to the right spot.

There is an SST that does it perfectly, but it's unobtanium through Mr. T now and the ones online are like $400. Page 57 has the info you need.

Otherwise, try the 40 section.

 

[Dennis 1970 40]

I laid a ruler across the top of the booster over the pushrod of the old unit and measured. Matched up the distance on the new. Gravy

Honestly, this is one of the trickiest things I have ever fiddled with on an 80. There is no good way to measure the depth with normal gauges and the push rod moves in and out and it's extremely frustrating to try to get it to mate with the MC right. That said, 3/4" might as well be a mile. It will be very, very close to the factory settings, but if you lose those by adjusting it, good luck. I ended up just getting a different booster that was already set to the right spot.

There is an SST that does it perfectly, but it's unobtanium through Mr. T now and the ones online are like $400. Page 57 has the info you need.

Otherwise, try the 40 section.

Thanks for the information. The original length of the rod was almost at minimum, I'm now 3/4" longer and finally I can feel the booster having an effect on braking. That's why I was thinking wrong booster installed. (they purchased from Track Auto and it was a backyard removal and installation without any adjustments whatsoever. I'm thinking just the wrong booster at this point. I did read a post about using a straightedge and get the depth of rod to MC and then do same for distance of rod into booster, Add up the two and add 0.001" and that's the correct length. I'm trying that on Saturday. I'll let folks know if a success.

 

[Red Merle]

The ruler idea would work if you knew whether to measure when the push rod is "in" or "out". You would need a helper though unless you have three hands.

 

[LandCruiserPhil]

For rod adjustment I just positioned the new and old side by side and used a level on top of the rod to make them exactly the same. Brake results were as good as before.

 

[Locked79]

I assume this is the measurement you need the sst for.

 

[Corbet]

For rod adjustment I just positioned the new and old side by side and used a level on top of the rod to make them exactly the same. Brake results were as good as before.

Phil, I don’t follow your logic here based on the FSM instructions with the SST. How does the level over the pedal side measure the push rod adjustment on the master cylinder side?

 

[landtank]

I made a very simple gauge that lets you set one side to you master cylinder and automatically sets the other side for guage the rod position.

My shop ran an extra 40 of these so anyone wanting one pm me. 5.00 includes first class mail.

 

[landtank]

Should explain how it works.

Place the flat bar across the master cylinder and adjust the center screw so it touches the bottom of the piston the the pushrod interfaces with.

Now adjust the outside screws so they touch the mounting face of the master cylinder.

Then lock down the nuts and use the other side of the screws to set you rod depth.

Either the outside screws resting on the mounting surface of the booster adjust the push rod SO IT TOUCHES the end if the screw.

The screw’s flat end and diameter automatically provide the appropriate gap to Toyota specs provided the push rod is touching the screw when adjusted.

 

[Corbet]

And I just ordered the tool from Summit Racing.…

 

[landtank]

And I just ordered the tool from Summit Racing.…

They take returns.

 

[Corbet]

Of course but at this point I’m committed, that will just be more work on my part.

 

[sunrk]

There is a factory tool for it. Hardest part is actually getting a non Chinese junk booster (I don't know if our RHD vehicles use the exact same boosters as LHD ones - better they have the vacuum inlet on the opposite side.

Plus there are soooooo many part numbers for the boosters you don't actually know which ones are interchangable. Made trickier with the older non-ABS 80's because OEM boosters are very NLA but there are apparently generic Japanese made ones that work.