Help needed installing new brake cylinder-booster combi

[Mr. Lee]

Hey guys, I bought this brake cylinder-booster combi and as there is no mounting instruction added I have some questions:




On this pic above it seems that the cylinder and booster are mounted without a gap between them, but when I install them there is a gap due to some bolts. You can see them press into the booster also on the pic. I guess the booster has already been slightly bend  

Do I need to remove these 2 bolts, or do I need to remove the bolts, gold colored part and the rubber thing all together?











And are there more things I need to think about? Thanks 

[BLK 68 R/T]

Remove the 2 small bolts, the gold retainer plate and the rubber bellow.

[70sixpkrt]

Remove the 2 small bolts, the gold retainer plate and the rubber bellow./quote]

   You don't need to use the boot.

[green69rt]

You may need to adjust the output plunger on the booster after removing the above.  You can see that it has a bolt and a lock nut.  You need to measure the depth of the hole in the MC and make sure the booster plunger just barely touched the piston inside the MC.  Also if this is like a lot of after market boosters, you may have to hog out the hole in the mounting bracket that attaches to the firewall and the firewall itself.  No big deal, maybe 1/8" or less.

Edit - just looked and you have the aftermarket bracket so ok, but the firewall may still need to be hogged out.

[b5blue]

Thought the factory has an alloy/rubber spacer thingy in between also? 

[BLK 68 R/T]

Thought the factory has an alloy/rubber spacer thingy in between also? 

No spacer on the Bendix booster that I'm aware of.

[venecharger]

Remove the 2 small bolts, the gold retainer plate and the rubber bellow./quote]

   You don't need to use the boot.

I bought the same kit and it should include a power booster type piston retainer. IMHO placing the M/C without it may cause leaks since the piston goes out from the cylinder showing its o-ring.

[venecharger]

You can see that power booster type retainer in this post:

http://www.dodgecharger.com/forum/index.php/topic,70877.0.html

[Mr. Lee]

IMHO placing the M/C without it may cause leaks since the piston goes out from the cylinder showing its o-ring.

Anyone else has an opinion about this matter?

I installed the MC without the 2 bolts, retainer and rubber. Didn't brake it yet, waiting for a frined now helping me bleeding the brakesysteem.
But yeah, o-ring comes out of the MC a bit so would that cause problems?

[green69rt]

IMHO placing the M/C without it may cause leaks since the piston goes out from the cylinder showing its o-ring.

Anyone else has an opinion about this matter?

I installed the MC without the 2 bolts, retainer and rubber. Didn't brake it yet, waiting for a frined now helping me bleeding the brakesysteem.
But yeah, o-ring comes out of the MC a bit so would that cause problems?

Yeah, when I saw mine I could see the o-ring.  When you install the MC on the booster the output shaft on the booster should push the piston till it sets flush with the body of the MC (preloaded in otherwords).  And you ask - "how will I know because I can't see it?"  What you have to do is measure the depth of the hole in the  MC piston.  Then adjust the reach of the output shaft so it should just barely touch the bottom of the hole in the piston when the piston is flush with the body of the MC.  Now comes the tricky part.  As you bolt the MC to the booster you can look down between the MC and booster and see the piston sticking out.  As you tighten the MC bolts, and if you adjusted the output piston correctly, you will see the piston being pushed back into the body of the MC.   This needs to be fairly accurate but not withing 1 or 2 thousandths of an inch, not that critical.  The problem is that if you don't get the piston far enough into the MC (preloaded) , when you step on the brake - a lot of the brake pedal travel is used up getting the output shaft to engage the piston and in the worst case you won't have any brakes.  At the other end of adjustment, if the piston is pushed too far then your brakes may be engaged all the time and overheat.

For example; the depth of the hole is 7/8 inch.  Adjust the output piston so it protrudes 7/8 inch beyond the bolting face of the booster.

You'll have a good idea that you did everything right when you go to bleed the brakes.  The brake pedal will not have a lot of travel (maybe 1/2") before you meet resistance and it will also have a good stroke that will allow you to bleed the brakes.  If the output shaft is to far out you won't be able to move the piston thru it's full stroke and bleeding will take forever.

[Mr. Lee]

I didn't adjust the output shaft. I did measure the dept of the piston in the MC with a screwdriver and put a tape around it. Held the taped screwdriver next to the output shaft and it looked like the same length.

So when the bolts, retainer and rubber where still on the MC I guess the combination MC and output shaft should be adjusted to eachother right? If that's so, the output shaft will push the piston back in to the MC now at the smae position it was when the bolts, retainer and rubber where still on right? Or am I thinking too easy?

[green69rt]

I didn't adjust the output shaft. I did measure the dept of the piston in the MC with a screwdriver and put a tape around it. Held the taped screwdriver next to the output shaft and it looked like the same length.

So when the bolts, retainer and rubber where still on the MC I guess the combination MC and output shaft should be adjusted to eachother right? If that's so, the output shaft will push the piston back in to the MC now at the smae position it was when the bolts, retainer and rubber where still on right? Or am I thinking too easy?

I wouldn't bet on it.  Measuring is best.   When you measure how far the output shaft is protruding, put a lat edge across the bolt face of the booster and measure from where the straight edge crosses the shaft to the end.  Watch how things move when you bolt the MC on the booster.  Then a good test is bleeding, like I said.  Final test is on the first test drive and everyone survives..

[venecharger]

Looking the m/c, perhaps there´s no issue or need for preloading since the plunger has a retaining bolt downside its body.

Anyway, part vendor should give better info to consumers.

[green69rt]

Looking the m/c, perhaps there´s no issue or need for preloading since the plunger has a retaining bolt downside its body.

Anyway, part vendor should give better info to consumers.

Yes there is a retaining screw down inside the body.  That's what keeps the piston from poping out of the MC completely.  The purpose of measuring the output shaft is to insure that there is a not a lot of play in the brake pedal before it starts to move the MC piston.   Somebody that has more experience with this needs to chime in, I'm only relating my experience and what I saw when I installed mine.  And yes the vendor needs to make their instructions clearer, I didn't see any with mine.

[Mr. Lee]

Well thanks for now guys, I did measure somewhat and think that it's about okay.

Next weekend my buddy will help me out with the bleeding and we'll see what happens