The long awaited LONG answer:
The LONG Tale of the Master Power Brake Disc Brake Conversion ('68 Charger)
Summary: I would never buy anything from Master Power Brakes again. "You" can
do what "you" want to.
Back in May or June, it seems so long ago and I don't remember, I ordered a
power disc brake conversion kit for my '68 Charger. It arrived about a week or
so later. While I was waiting, I took apart the whole front end, put in new
torsion bars, and a PST front end Super Kit. I wouldn't buy their parts again
either but that is a whole different story.
The brake parts arrived and I started installing them. The caliper brackets
bolted right on. The left side rotor went right on. The right side didn't.
The caliper bracket had an extra large bump in the casting that hit the rotor.
Out came the file. Next step was to install the calipers. Left side went
right on. Right side didn't. Pad was hitting the caliper bracket. More
filing on the pad this time.
Next step of the "Bolt-on" process was installing the hydraulic lines. They
would have fit fine had the vehicle not had upper control arms or a "frame".
However, since a Charger has both (kind of, I know it's a unibody), the lines
don't fit. This led to the first call to MP Brakes where I was told that they
haven't had that problem before. They recommended bending the steel line at
the banjo fitting. To me, bending doesn't fall under the definition of
"bolt-on". So, I bent the lines to allow them to clear the calipers and the
control arms. Now, however, they need to enter the frame mounted brake line
from the top side instead of the bottom side like the original hoses did.
There goes the year old brake lines. All new lines needed to be bent for the
So, we finally get everything put together and bleed the brakes. Just to let
you know, the rear brakes had been done in the spring. All new springs, wheel
cylinders, shoes, and nicely turned drums. The only old part left in the brake
system was the brake pedal.
As we pulled out of the garage and slowly drove up the street, we prepared for
the first brake test. Fred Flinstone's car stops faster. Slowly drove around
the subdivision stopping all over. Tried to do some hard stops and basically
the car would coast to a stop.
Called MP Brakes and they recommended bleeding the brakes. We did it again
knowing that there was nothing wrong with how they were bled the first time.
No difference in braking.
Called MP Brakes again. They agreed to send me their pressure gage as a loaner
after I explained that if I bought something for $800 at the local store and it
didn't work that I would take it back. Did a pressure test and had 800 psi at
the front brakes and 650psi at the rear brakes. This is at or above their
Called MP Brakes again. They told me to go buy a new set of pads to try and
that they would pay for them. Installed the new pads and there was no
difference in braking.
Called MP Brakes again. This time they decided to send me a new booster. I
didn't think there was anything wrong with their original booster based on
disconnecting the vacuum line one time to see how the car would stop. There
was a noticeable difference with and without vacuum. The new booster came.
Anyone who has changed a power booster on a '68 B-body knows how much fun it
is. Put the new booster on and no difference.
I had also talked to one of the brake engineers at work. He was thinking that
a master cylinder with a smaller piston diameter would help. The MP Brakes kit
comes with a GM master cylinder that has a 1 1/8" diameter. The Chrysler
master cylinder has a 1" diameter piston.
After the new booster didn't work, we installed the original booster and master
cylinder that were on the car before this "bolt-on" project started. Amazingly
enough I had brakes. I could finally lock up the front wheels on pavement.
The rears won't lock up. The fronts wouldn't even lock up on dirt with the MP
Brakes booster and master cylinder.
Called MP Brakes again. Told them that I wanted the Chrysler disc/drum master
cylinder that they have listed on their web site. I also wanted it shipped
overnight which they agreed to once I agreed to pay half of the shipping.
I talked to the brake engineer at work again. He said he had spent some time
going through the MP Brakes web site and had come to the conclusion that the
master cylinder and the brake booster from the kit were both inadequate for the
He gave me a brake pedal force vs deceleration tester to try out. The car will
stop at about 0.8-0.82g's with 50-90lbs of pedal force. The front wheels start
to lock-up at this braking level. The brake engineer felt that 0.8 g's was a
good level for the car considering it doesn't have ABS. Based on the data with
lower pedal forces, he also asked if the brakes seem to come on rather quickly
which they do. At least the car stops and I'm not afraid to drive it.
My recommendation to anyone who wants to do the conversion is to NOT buy the
kit from MP Brakes. I know some of you have bought it and have not had any
troubles. Why I had these problems, I don't know but I wouldn't want anyone
else to go through it. MP Brakes did refund me the cost of the pads and the
booster that I didn't need minus the cost of the overnight shipping after I
sent them the two boosters and the master cylinder (they paid shipping). I
even got to keep the pressure gage which is of dubious quality based on how
badly the housing is cracking and falling apart.
Some parts you need to do it yourself:
Pads are part number D84. They fit Aspens/Volares. Calipers and rotors also
fit Aspen/Volare. Master cylinder is a Bendix 11571 (4 bolt)which can be
ordered from any part store that sells Bendix parts. Use the 9" booster (4
bolt) that you already have. You'll need a combination valve. If you want new
spindles and caliper brackets, you may have to buy them from MP Brakes. I
would try to find them somewhere else first.
I don't know if MP Brakes did any engineering to try to figure out this kit.
My guess is they didn't. I sure got to do a lot of extra work.
Glad it's fixed in time to cruise Woodward.
Post by Raffi3834
I just got the "Master Power Brake conversion" working on my '68 Charger.
DON'T BUY THEIR KIT.
Their booster is too small and the GM master cylinder they sell you has too big
a bore diameter. Car would barely stop.
Do the "A" body conversion.
More details after I get my refund for all of the parts I sent back.
Post by Blaster!
So I am thinking it is time to ditch the drums on my 67 Coronet. I can use
OEM parts, Stainless Steel, Wildwood...what do I gain by sticking with Mopar
factory stuff besides more money in the bank? The SSBrakes seem good with a
four piston design but will I run into problems getting replacement parts if
needed? Will Wildwoods stand up to a daily driver?
And lastly...power or no power? It is a daily driver w/318 and maybe...just
maybe...get a crate 360 for it but no big block.
Thanks for the advice!
(Scrap the ford to reply. I'm tired of the junk mail.)