Big MBM Front Disc Conversion problem

[aswert1223]

I got the MBM kit through Summit several weeks ago.  Details: http://www.dodgecharger.com/forum/index.php/topic,18451.0.html.

Today I finally got to installation of the booster/master cylinder.  Here is my old power 4 wheel drum unit bolted together on the bench:


Bottom-up view:


The kit includes this bracket:


Another view:


My first problem is that this bracket is junk.  All of the moving parts have terrible "slop".  The bottom pivot bolt has a nylon lock nut, but the bolt is so short that the nut does not lock.  As delivered, this bolt will definately fall out and disconnect the pedal from the master cylinder .

Now the next (worst) problem:


If you look closely at the picture above, you see that the pushrod for the power booster would be sticking through the firewall.  In this picture, the rod is threaded all the way in (i.e. shortest adjustment).  I think I can cut it and get clearance, but since this bracket is non-adjustable, the geometry may be wrong and not work properly.

Even if the rod castration works, there is no good way to seal the hole in the firewall where the pedal pushrod enters the cabin.

Has anyone mounted one of these things on a second generation Charger? 

I plan on calling MBM tomorrow and seeing if they have any help for me, but I do not have much hope.  Even if this bracket works, it will rattle, leak fumes from the engine bay, and may come apart at any moment.

I think I am going to try and find a more direct-fit power booster and abandon this one.

BTW the rest of the brake kit seems to be good quality and fits well.

I don't think I ever posted pics of my 1970 Charger 500 here before; here are a few :








Cheesy tach is gone now, Tic Tok Tach baby

[Silver R/T]

nice charger

[blue69]

I never installed a booster like that but it looks similar to the booster relocation bracket used on hemi cars. You might be able to use a firewall boot from a hemi car. I think this is the correct one http://cgi.ebay.com/ebaymotors/Brake-Booster-Boot-Charger-Coronet-66-67-68-69-70-HEMI_W0QQcmdZViewItemQQcategoryZ34206QQihZ011QQitemZ320015768402QQrdZ1QQsspagenameZWD1V

[aswert1223]

UPDATE 12-01-06

Summit seems to be aware of problems with this mounting bracket.  Since the kit was invoiced as 3 separate line items (ROTORS ABD BRAKE LINES, CALIPERS SPINDLES SEALS HDRW, & BOOSTER(8") MASTER PEDAL KIT), Summit will take back the bracket, booster, & master cylinder and refund $246.46  .

My current paln is to send my original 4 wheel drum booster for rebuild & refinish.  I spoke to Anwar at http://www.braketechsolutions.com/ in Charlotte, NC.  He will rebuild my original and refinish in black for $295 of cad for $320.  He also will supply the proper disc / drum master cylinder for ~$50.  Estimated turn around time for the booster is 7 -10 days.

Jack   

[Chatt69chgr]

The booster for a drum application is different than the one for a disc applicaton.  Disc's use a dual diaphram booster.  Usually a Bendix dual diaphram for 68 to 70 B-bodies with disc brakes.  The bracket they supplied you is used with A-bodys and I think in Hemi applications and mounts on the engine side of the firewall.  The new booster they supplied you does not appear to have the proper length brake pushrod and it's not the right kind anyway.  It looks like one for a C body where the pushrod attaches directly to the brake pedal.  The proper booster for a B-body disc application will have the brake pushrod attach to the fulcrum mechanism just like you showed in your first picture.  That pushrod will extend just past the dust bellows.  Not a inch and a half to two inches past like the one you got.  I have no idea whether you can use a drum booster with a disc application.  Someone else with more knowledge than me will need to answer that.  MBM Brakes has a website that you can access with google.  They are located in Asheville, NC.  Their retail outlet is Pirate Jacks also in Asheville.  And they  show in their 2007 catalog a picture of the booster you need.  It is a PB8536.  Only trouble is it is "coming soon" and has been coming soon for a year.  If enough people raise cain with them, maybe they will kick enough Chinese butt to get this unit available now.  And I will note that if they don't, we are all screwed since there is now no availability of this booster on the rebuilt market.  They dried up about a month ago.  Its return and repair now.  So if you don't have a core, tough stuff----if you want to use a booster.  Some say that the brakes work adequately with no booster.  In this case, the pushrod from the master connects directly to the brake pedal and you don't use the fulcrum mechanism.  Note that the firewall stiffener plate is different for the non-booster application in that it has a smaller hole for the brake pushrod to pass through.  In these applications, the master is attached on the lower four holes.  You can find tons of these stiffener plates in the junkyard so that should be no problem. 

[mopar0166]

good stuff ran into the same problem, i actully lowered the hole for the pedal to make it work , but its hangin up big time very hard to push and it doesent return correctly??   what can i do ?