I just received my new Raybestos M/C (Part# MC36221) for my 1966 Dodge Dart brake upgrade . This new M/C was supposed to fit a 1967 Dart with manual drum brakes all around.
I was told this later year M/C would be a direct bolt on dual chamber upgrade for my single stock one.
All the correct lines, couplers, & fittings are ready to go for this job except I am having a problem understanding how the old pushrod is held in place inside the new M/C???
My old,stock single M/C came with a pushrod already installed with a rubber boot. The upgrade instructions I am following, tells me to use my old, stock pushrod in the new M/C. Because my old pushrod is held in place in the old unit with some kind of rubber retainer ring, I understand I have to force the rod out.
My new M/C has just a smooth bore & doesn't seem to have provisions to keep my old rod in place. Will my old rod keep the rubber in place to push into the new M/C, or am I using the wrong M/C for this upgrade??
I'm afraid if the new M/C cannot hold my old rod in place, it may pop out of the bore while operating the brake pedal! Any help is greatly appreciated!!

See Link To Pics. Below:


http://i490.photobucket.com/albums/rr26 ... P60049.jpg

http://i490.photobucket.com/albums/rr26 ... P60053.jpg

That's a power-brake master cylinder. Those don't have the stepped bore in the rear of the piston to hold the pushrod retainer.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

[quote="SlantSixDan"]That's a power-brake master cylinder. Those don't have the stepped bore in the rear of the piston to hold the pushrod retainer.[/quote]

Thank's SlantSixDan! I kinda thought it might not be the correct M/C.
Every search I did for a 1967 Dart with manual drums came up with the Raybestos # MC36221.
Do you think they just boxed the wrong M/C or is the MC36221 just the wrong listing for the 4 wheel drum manual brakes??
Would you happen to know which dual M/C upgrade would work for my 1966 Dart with 4 drum manual brakes?
Thanks Again!

After inspecting the bore in the new M/C more closely, I did find a slightly larger recess in the pushrod bore. It was very hard to see, but the bore is definitely enlarged at the very bottom.
I have tried to find another Raybestos part# for a 1967 Dart 4 wheel drum,manual brake car & the MC36221 M/C keeps popping up.
I guess the only way to really find out if this M/C will work is to pop the old pushrod from single M/C & see if it will fit.
I guess I should also use the old boot, spring, & boot clip from the old M/C too???
Funny thing is that Cardone does list 2 different M/C's for power vs manual brakes in '67, but Raybestos only list the 1 part #. I didn't want to order this brand because they only had the remanufactured one's.

Smart choice avoiding Cardone's garbage.

The step you're looking for isn't at the bottom of the piston's rear bore, it's actually just inside (at the "top").

Take a look at a Raybestos MC36338; that should be the one you need.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

[quote="SlantSixDan"]Smart choice avoiding Cardone's garbage.

The step you're looking for isn't at the bottom of the piston's rear bore, it's actually just inside (at the "top").

Take a look at a Raybestos MC36338; that should be the one you need.[/quote]

Thank's again Dan!! I really appreciate your help. I see the MC36338 you suggested fits darts starting in 1971. You would think the one listed for 1967 to1970 would be the better fit.
One other question please: I see from the specs on the MC36338 that the bore diameter is 15/16". My stock single pod Raybestos has a 1" bore. Will this make for any problems with the stopping characteristics from the stock single M/C?
FYI: I am planning to do the upgrade that plugs the rear port on the stock '66 junction block & runs the dedicated rear line to the front port of the new M/C. The rear port of the new M/C will go to the original junction inlet to feed the front brakes.
Steve

I found an old single pot M/C for the dart tucked away in the garage & decided to do some Sunday experimenting. I placed the old M/C in a bench vice, placed a very long bolt through the plunger rod's pedal mounting eye, & with several blows from the 10lb hammer, the rod end came out of the bore, rubber retainer intact!!!
I then took my caliper & measured the inside bore depth on both the old single M/C & the new Raybestos MC36221. Identical!
Turns out the new M/C has the relief cut out in the correct spot near the bottom of the plunger bore. I test fitted to make sure.
The old M/C has a different hold down system for the plunger. It is slightly raised around the plunger to accomodate the old boot & spring which the old rod uses. The new M/C uses 2 arrow shaped hold down tabs to hold the plunger in place.
Now to see if things would interchange. I loosened one of the old plunger retainer ring bolts slightly & swung the ring just far enough away to accomodate the pointed retainer tab off the new M/C. I then removed one of the new retainer tabs along with the short screw & screwed it into the retainer hole & it fit perfectly! Now it was just a matter of swinging the retaining ring into place & replacing the bolt. I also replaced the other pointed retainer on the old M/C. The above was done in this manner so the plunger would not pop out of either M/C while I was performing the switch.
The last thing I did was slide the spring, boot & retainer ring back onto the old rod & install back into the new M/C.
Everything looks great! Now if it were warmer I will install on the Dart to see how it performes.
Will follow up & thanks again to Dan for your help!
Steve

those tin retainer tabs are there strictly for shipping purposes, as are the countersunk screws. do not use them in your car.

also, do not reuse the old rubber retainer because you do not have to. shipped with your raybestos master cylinder will be a bag containing instructions, four plastic plugs to facilitate bench bleeding your master cylinder, which MUST be done (your instruction leaflet will walk you through it) and, one new rubber retainer. if this bag is missing return the master cylinder for another one.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

There is no way in which a '67-'70 master is a better fit than a '71-up master on a '66 car.
The slightly smaller bore would give you slightly lower pedal effort and slightly longer pedal travel.

I'm not confident that what you found in the #36221 is in fact a bore step intended to take the rubber pushrod retainer grommet. The larger-diameter area in the piston counterbore needs to have two distinct edges, one at the leading edge and one at the trailing edge, so the grommet cannot move relative to the piston. If the grommet can move, there will be lost motion in the brake pedal as the grommet slides back and forth in the piston. Also, as I say, the grommet area in the piston is not located near the bottom of the counterbore, it's located near the top.

For future reference, the easy way to remove the pushrod from the master is to put the master on the firewall studs, turn the nuts onto the studs just a few threads, hook the pushrod up to the brake pedal (just finger-tighten the nut and bolt), wedge a piece of wood or something between firewall and master cylinder, and jerk the brake pedal firmly upward.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

[quote]There is no way in which a '67-'70 master is a better fit than a '71-up master on a '66 car.
[/quote]

Sorry Dan, I wasn't meaning to challenge your knowledge of which is a better fit for my '66 Dart. As I stated, you would think the very next generation of this M/C would be a better fit. Not that it is.

[quote]The slightly smaller bore would give you slightly lower pedal effort and slightly longer pedal travel.[/quote]

Good Info!I totally agree Dan. The pedal firmness & travel was fine for me with the old M/C so I just figured the same size bore would not chang this.
Thank's for the tip on removing the old pushrod.I'll definitely remember it. Unfortunately, the old M/C I found wasn't installed on the car so I couldn't use the pedal for leverage.

The larger-diameter in the piston counterbore on the #36221 is showing the 2 edges for the grommet, at the the bottom of the bore, exactly where it is on the old, single M/C. The rod itself has the grommet installed just below the rounded edge. If the grommet area in the piston was located near the top of the bore, the rod would never be fully seated.
See link to pics:
http://i490.photobucket.com/albums/rr26 ... P60060.jpg
http://i490.photobucket.com/albums/rr26 ... P60057.jpg
http://i490.photobucket.com/albums/rr26 ... P60059.jpg
I'll be sure to let you know how this all works out. Right now everything fits great & there is no play in the rod installed into the #36221, but I won't be able to test until it gets a little warmer outside.
Thank's Again Dan!!!
Steve

Didn't seem to me as if that's what you were doing - I (mis?)read you as suggesting there was a fit/compatibility issue.
Ah! Then you're all set.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

Boy, you would think they would have that info to remove the shipping tabs in bold letters inside the instruction!! Thank's Steponmebbbboom!
I thought those short screws & 2 small retainer tabs were uundersized to hold the piston in place.I did the correct transfer of parts without even realizing this!
Yes, I did find the bag of plugs along with the new rubber grommet.
Now if I could just make this cold weather go away, I could install the new M/C to see if the upgrade works!
Thank's For The Great Tips! I Really Appreciate Them!
Steve

another tip steve, if you click the profile tab near the top of the screen it will take you to your profile preferences. near the bottom of the screen there will be a series of checkboxes, one will be labeled "always allow bbCode". if you switch it over to "yes" you will be able to quote properly.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

Hi Dan,
I forgot to ask you, besides the longer travel & lower pedal effort(Due to smaller bore size) , what is the other benefit to using the # MC36338 instead of the earlier # MC36221 for my upgrade?
Sorry for asking so many questions. I just want to make sure everything is correct before I actually do the upgrade.
Don't be afraid to criticize, thats how I learn!
Thank's,
Steve

Thank's!! I was wondering why my quote marks always looked like "Quote marks!"