Brake Servo/Booster adjustment

[dinosabella]

I am halfway done trying to replace my brake servo on my 77 Spider. It was a PITA getting that thing out of the engine bay, had to remove the carb and the brake fluid reservoir just to have enough room to muscle it out,,,barely. I will be fun trying to get the new one back in that tight spot.

The good news is that I haven't lost or broke anything, I did however spill a lot of brake fluid onto the engine bay.

I have the Haynes Manual and the instructions seem pretty straight forward in installation but I have have been reading on the International Auto website that there is an adjustment to the acorn protrusion part on the brake booster.

The instructions seem a little complicated. Couldn't I try to match-up the new acorn to the set-up on my old brake booster?

Thanks

[azruss]

I know the adjustment is a PITA but it controls how much pedal travel you have before the booster works. If its too tight, it will create brake drag. You have it apart now, so better to bite the bullet rather than having to take it apart again if the adjustment isnt right.

[donm]

As Azruss said, the adjustment of the acorn nut also affects the pedal travel. It's tricky trying to get the least amount of travel without having the brakes drag.
To get to what I thought was the optimum point I left the master cylinder mounting nuts loose enough so I could pull the cylinder away from the booster and reach in to get at the acorn nut. Then I did some test driving. In my case the brake lines going to the cylinder had enough slack in them so I could do this without disconnecting them.

[dinosabella]

Had I know about this delicate adjustment before I took apart half the car I never would have done it lol. I would have let the mechanic figure it out.

Could someone please give me a "for dummies" instruction on how to adjust and measure this famous acorn?

Thanks again!

[Kevin1]

After a lot of trouble measuring the position of the acorn nut on disassembly, and trying to set it up the same on the new one I found out that didn't work (at least for me). The new booster just wasn't the same somehow, and the acorn nut became a trial and error exercise to get it right. Mine ended up only half a turn from being seated at it's shortest length. With the original booster the acorn nut was at least ten turns from bottom.

It takes a few rounds of removing the master cylinder / adjusting the acorn nut/ trying the brakes to get it right.

[azruss]

As I recall, i used a dial caliper to measure the top of the nut to the booster body. I think the haynes manual should spec this. If you can set to that spec, you should be good to go.