Setting the brake pedal rod depth Options

[VaccaRabite]

I have recently changed my brake master, and I've had some issues.

One of the things that was suggested was that the rod from the brake pedal to the master may not be the correct depth.

The rod was set perfectly for the prior master, but that was 17 years ago.

I'm going to pull the pedal cluster out to check depth. What is the right way to make sure the plunger is the right length?

Zach

[sixnotfour]

yes and you don't have to pull pedal cluster...
you should feel a little play between end of rod and master..
call it free play ,, a rattle ,, an exact mm is somewhere..

[bdstone914]

I have recently changed my brake master, and I've had some issues.

One of the things that was suggested was that the rod from the brake pedal to the master may not be the correct depth.

The rod was set perfectly for the prior master, but that was 17 years ago.

I'm going to pull the pedal cluster out to check depth. What is the right way to make sure the plunger is the right length?

Zach

You don't need to pull the cluster to check the depth. The rid should allow about 1" brake oedal movement before it moves the piston on the master cylinder. That is per the factory spec. I like less play. Loosen the jam nut on the brake rod and turn it to extend the lenght. You should be able to feel when it is starting to move the piston. The tmrod has a nut to turn it but it is best done by hand.
By any chance was the previous master sized. I see brake rods that are bent on a lot of pedal sets. I think that they bend when the master is siezed and extreme force is used to depress the pedal.

[VaccaRabite]

By any chance was the previous master sized. I see brake rods that are bent on a lot of pedal sets. I think that they bend when the master is siezed and extreme force is used to depress the pedal.

No. Best as I can tell the old cylinder had the internal valving/seals fail. And once I pumped it back up it held pressure again - but it was 17 years old so I replaced it.

Zach

[flyer86d]

Boy, did this post come at the right time. I tried to back the 68 911 out of the garage for the first time of the year and all of the brakes were locked up. I had rebuilt the calipers in 2021, installed a new master and rubber lines at that time.So I jacked it up and removed and cleaned all 4 calipers. I saw this post and checked the rod depth. It wasn’t allowing the brakes to release! I readjusted it this morning and all is well.

Thank you 914world!

Charlie

[bdstone914]

By any chance was the previous master sized. I see brake rods that are bent on a lot of pedal sets. I think that they bend when the master is siezed and extreme force is used to depress the pedal.

No. Best as I can tell the old cylinder had the internal valving/seals fail. And once I pumped it back up it held pressure again - but it was 17 years old so I replaced it.

Zach

.Did you get it adjusted
.

[iankarr]

It's pretty easy. Loosen the nut(s) that Bruce pointed out and extend the rod until it kisses the MC piston. Then back it off a half turn. I think the factory spec for the gap is 1mm. What you don't want is the pushrod making contact with the piston while the pedal is in its resting position.

[VaccaRabite]

By any chance was the previous master sized. I see brake rods that are bent on a lot of pedal sets. I think that they bend when the master is siezed and extreme force is used to depress the pedal.

No. Best as I can tell the old cylinder had the internal valving/seals fail. And once I pumped it back up it held pressure again - but it was 17 years old so I replaced it.

Zach

.Did you get it adjusted
.

Boy Scouts. Eagle Project. College applications. End of the school year programs.
I have not seen the inside of my garage since I posted this thread. I'm hoping to get some time this weekend, but my eldest has me pretty scheduled out supporting events.

Zach