Drums to discs. Do I change m/cylinder?

[TimDart]

I've just been reading the ultimate brake swap article...

http://www.moparaction.com/Tech/archive/disc-main.html

...which, towards the end suggests that i don't neccasarily have to change master cylinder.

my car is '74 Dart and i'm swapping drums out for a complete disc brake set up from another '73/74 Dart.

I don't want power brakes and booster, so can I use my drum m/cylinder to stop the disc brakes?

 

[RedFish]

If the current master cylinder is good I'd try it. Once a new one is needed the correct disc brake master would be best.

 

[crackedback]

There may be a small residual valve in your drum master to hold pressure in the line. If swapping to a disc set up, you don't want that valve in the master. It's usually a small brass piece located where the lines hook up to the master.

 

[dgc333]

The biggest reason to get the proper disk brake MC is that there is not enough fluid in the drum brake MC to allow for full wear of the pads. That is the reason that disk/drum MCs have a bigger reservoir for the disk side.

A rebuilt disk MC is only about $20 at your local Autozone or Advance, why not just get the correct one to start with.

 

[edbux]

Yes, get the correct one. That might eliminate that lil voice in your head saying "why didn't I spend the $20 on the correct mc?" when it's time for the first hard stop. Old mc...cheap...peace of mind....priceless.

You can get an aluminum mc for an 80's truck complete with reservoir for around $60. But you'll need to spend the extra money for an adapter (4 bolt to 2 bolt). Looks nicer, probably a better design and the outside won't rust
on you. Plus, you don't have that bar that needs prying to get the cap off.

 

[BrianT]

I just received this in the mail today!

http://cgi.ebay.com/ebaymotors/ws/e...STRK:MEWN:IT&viewitem=&item=280254648156&rd=1

I will be doing the disc brake/big rear brake swap in the next few weeks.

 

[Dakota_Don]

thats an 87 dodge truck MC.. but the bracket looks nice, also what about your brake pedal rod?

 

[TimDart]

OK, thanks guys,that confirms for me. I have to ship the mc to the UK, so it's not quite so cheap. That said, i'm not going to skimp when it comes to safety!

 

[BrianT]

thats an 87 dodge truck MC.. but the bracket looks nice, also what about your brake pedal rod?

Is there a problem using this master cyl? I am using 11" truck rear brakes.

I have manual brakes now and was told that I could use the same rod.

 

[C130 Chief]

Do you have to comply with MOT or what ever the safety inspection is over there? If so, I would venture to guess that the most professional or factory looking installation will be of some advantage. "Hacked" looking brakes will probably cause problems.

 

[TimDart]

Chief, the MOT is a strange beast. As long as the brakes work and there are no leaks, all is ok. This year, for the first time in 5 MOT tests, my car 'failed' on the lack of rar reflectors.Stuck two cycle ones on, passed the test and promptly pulled them of.
The strange world of over zealous regulation!

 

[Dakota_Don]

thats what i was wondering if the same rod can be use, the Mc is 1 1/8 bore i dont know if there would be a problem using it or not.. but i would like to know my self, cuz i am doing a 68 dart disc upgrade myself

 

[388dart]

check the fluid level once in a while - thats good safety and saves a MC swap for no usefull purpose - M2CsW - mine works just fine.

 

[BrianT]

thats what i was wondering if the same rod can be use, the Mc is 1 1/8 bore i dont know if there would be a problem using it or not.. but i would like to know my self, cuz i am doing a 68 dart disc upgrade myself

I was told that with the 1 1/8 bore that the pedal will be hard, but I'm not worried about that. Supposedly, the stock rod will work.

 

[jefflock]

I used the stock rod when I installed that aluminum master cylinder on my 68 Dart. I purchased it from Rick also,

 

[charger70]

I was told that with the 1 1/8 bore that the pedal will be hard, but I'm not worried about that. Supposedly, the stock rod will work.

I see you bought it from "the Man" himself, R Ehrenberg. I have one on my 71 and bought it thru Mopar a couple years ago. Way more $$.

 

[BrianT]

I have heard other people talk about him, but I have no idea who he is. Some magazine guy?

 

[FISHBREATH]

He is an engineer and the Tech Editor for one of the MOPAR mags, either MOPAR Muscle or MOPAR Action, I get both and I forget which one he is with.

 

[abodyjoe]

I have heard other people talk about him, but I have no idea who he is. Some magazine guy?

he is the *** that writes for mopar action. was good years ago but in recent years he had gotten a little big headed for my taste.

 

[rumblefish360]

Don't ya mean pig headed, full of himself?

I thought there was a pushrod length issue. The pushrod needed a little extension cap for this kit above?

Now, is there a problem with an OE unit being used? Swap out drum/drum MC for a disc/drum MC?

 

[abodyjoe]

Don't ya mean pig headed, full of himself?

I thought there was a pushrod length issue. The pushrod needed a little extension cap for this kit above?

Now, is there a problem with an OE unit being used? Swap out drum/drum MC for a disc/drum MC?

yea that about nails him...lol.


i didn't need an extension. with that spacer/adapter. i believe the inside of the master cyl. has a shallower bore then the stock disc brake master.

 

[rumblefish360]

Hummmm, that makes me want to try that ASAP. I need the adapter, I have spare masters.

Thanks Joe