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Booster push rod adjustment

X

xatu40

CJ-8 Member
Gold Member
City
Port Orange
State
FL
Installing a new master cylinder and booster. I didn't know that the push rod depth in the booster had to be set. Figured since they came as a set, they'd be compatible. Ordered the tool to check it and I got it close, but I need another 1/32 - 1/16 of an inch. 8c67c24a-1c1f-43ce-a409-36d578c78b88-1_all_5238.jpg

Is there another adjustment that can be done on the booster to pull the push rod in a little more?

If not, I'm thinking one of the following:
A. Grind the top of the push rod head down.
B. File down the master cylinder pushrod adapter.
C. Put a washer on the mounting studs between the booster and master cylinder and set the push rod for this configuration.
D. Try it as.

I'm leaning towards Option C, but would appreciate any first hand experience.

Thanks!
 
Tri county gear used to make an adjustable pushrod but seems they may be out of business.
 
barrys said:
Tri county gear used to make an adjustable pushrod but seems they may be out of business.
Click to expand...
Wasn't that the rod from the pedal? Seems like I remember seeing that in magazines back in the late 90's?
 
Not first hand experience....

But for <1/16", I'd probably go with option D.

If I were to try to shorten it, I'd probably grind down what ever is keeping it from getting shorter... internal threads, external threads, or both of adjustment mechanism..
 
Does it have the little rod in the MC that is pushed by the rod from the booster? Mine was able to be removed easily. It looks like it could be ground shorter in my application. But mine worked out of the box with my kit. Are you syre it needs shortening? Personally, I would try it out as is. Not a horrible job to remove and adjust later if needed.
 
gr8dain said:
Does it have the little rod in the MC that is pushed by the rod from the booster? Mine was able to be removed easily. It looks like it could be ground shorter in my application. But mine worked out of the box with my kit. Are you syre it needs shortening? Personally, I would try it out as is. Not a horrible job to remove and adjust later if needed.
Click to expand...
Yes, that was my option B. It came with no instructions, found the MBM instructions online and they don't mention adjusting it. But my analysis paralysis led me to multiple youtube videos saying it should be done. Leaning towards trying it as is. Appreciate the feedback!
 
Why can you only lengthen it? Assuming it is threaded, couldn't you thread it further. Then cut it down. Like shortening a bolt.
 
It has a fixed length rod coming through the booster. As in the first picture above and the schematic below, there is a locking nut and the adjustment bolt. Currently have the adjustment bolt in as far as it can go. To get any additional clearance on this component, I think the option would be to flatten the head of that adjustment bolt some.
1718190749632.png
 
You have a very unusual situation going on if your measurements are correct. Make sure you don't have the attachment to the pedal(The adjustment on that side) too long which then would be "applying" the brakes. I have seen it before where the threaded rod into the clevis was pushing on the pedal arm too. If you completely disconnect the clevis from the pedal, you may get a different measurement.
 
I was worried about that and pulled the booster back out. Same measurement on the work bench.
 
If I were going to shorten it, I'd trim down the female side of the adjustment rod and, if necessary, the threaded end of the adjustment bolt (areas shown in red). This way the contact points remain "as manufactured".
1718198216055.png
Black: Adjustment Bolt
Grey: Lock Nut
Blue: Female Side of Adjustment Rod
 
xatu40 said:
It has a fixed length rod coming through the booster.
Click to expand...
The rod definitely comes out, it does not go all the way through the booster. If the rod went through the booster it would be direct drive on master which wouldn't boost anything. As you can see in your picture (post #15), it only goes half way. Here is a picture of a non-adjustable output rod, yours will be the same but with a nut instead of the rounded end:
rsd-r04_xl.jpg
 
mssldn said:
The rod definitely comes out, it does not go all the way through the booster. If the rod went through the booster it would be direct drive on master which wouldn't boost anything. As you can see in your picture (post #15), it only goes half way. Here is a picture of a non-adjustable output rod, yours will be the same but with a nut instead of the rounded end:
View attachment 113928
Click to expand...
Agreed. Poor word choice on my part.
 
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