new master cylinder or rebuild?

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needsaresto

needsaresto

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I have the original master for my KH brakes in my 70 Dart. The master needs rebuilt. I found a pro grade rebuild kit with stainless piston etc,everything you need and then some. But it is $38.00! Super looking stuff though. A brand new master is $46. Seems like a no brainer,but it's not a matter of money. The new master is likely chinese,and I should see it tommorow. The kit I have no clue where it's from.

I want the best master I can put in. Which way to go? Havent paid for anything yet.
 
THIS IS A NO BRAINER. Buy the new one ( !!!!??????You get to keep the old one, right!!!!????? )

The new one is guaranteed, "your" rebuild job is NOT
 
the old one is iron,,,the new one is aluminum,,plastic bottle,,,orignal looks important ????
 
You will likely not find an aluminum master cylinder with the same 1" bore as the original unit in your '70. If you have access to a good quality rebuild kit, I'd go that route. If I never wanted to have to do it again (or at least not for a very long time) I'd have my master cylinder sleeved with brass.
 
15/16 bore is available in a modern aluminum unit,,,thats what run with disc/drum combo,,,orignally available from mopar performance, now used in some dakotas,,,, he may get one of those,instead of an iron unit,,,
 
An alum unit would be fine. Would the alum master from an m body work?
 
the aluminum units only use a 2 bolt system,,,your orignal iron bolts on using 4 bolts,,,you will have to buy the 4 bolt to 2 bolt adapter, from a moparperformance dealer,, or maybe summit ?? or jegs??? macini has them,,

the question isnt will one from an M body work,,the question is,will it work properly,,or as well???
your car ,,,,4 drum ??? or disc /drum ??? manual or power ???? i have disc/drum,manual and i use an aluminum 2 bolt master 15/16 bore from a 1988 manual disc/drum dakota,,,,

the bigger the bore the harder it is to push the pedal,,,,your combo will decide what master you need,,,,do a search on rock auto .com
 
The car originally came with 10" drums all round. I bought a 4 piston KH system complete with p valve,spindles etc etc. Everything you need. Im stripping out the original master right now.The system I bought came with a power booster,but I'd like to go manual disc/drum with the original 10" drums out back and KH disc's.

The adaptor is no problem,I can make one easier than buying it. Getting the correct bore size master is a bit trickier.Did the Dak master require an adaptor?

Whats this about searching on rockauto? Do they have a special search engine to help guy's find the correct master in a custom app?
 
Rock auto replacement master has a 1" bore.

http://www.rockauto.com/catalog/moreinfo.php?pk=309048


This looks a lot like the master I saw a pic of at the parts store yesterday. It should be in today,so if it's a direct replacement alum master,we have a winner winner chicken dinner!! If this master is any good then we wont need to buy stupid adaptors that stress the booster mounting area.

I just got off the phone with my parts guy and this is the exact master he ordered in!! I'll have a good look at it,but he looked into thier warantee return info for me and there arent any returns. Raybestos is a brand I trust as well,thier lifetime pads/shoes are all I buy.
 
GGGGGGGGGGGGGGRRRRRRRRRRRRRRRRRR!!!!!!!!!!!!

Sometimes I hate jobber parts stores. The master shown on the internet is alum,but;this being Canada Lordco still has old cast iron masters in stock,so guess what was sent? Apparently Raybestos is in the process of changing thier old masters to alum.

They wont have any alum in stock until all the cast is gone. Whats wrong with them returning old stock?

Anyways,I dont wanna buy one through the internet. Maybe I'll try Napa. I need to have an alum master in my hands before I pay for it,because now Im nervous about any potential sellers dumping old stock on me.
 
Kinda seems like it's being pitched for a lot of apps.

I had a look at the raybestos cast iron pos. It looks nothing like the original,is bulkier and has a bolt thru the middle of the reservouir cap for a hold down. And it's made in china!!! FTS!

Im not buying that ...."thing". I can just bet installation will be a nightmare.

If it comes to it,I will just rebuild the original cast. As mentioned at least I will know what I've got.

I'd like a ready to go alum master for the weight savings,but I dont want a complication either.

Anyone using just a power master cyl without the vacuum booster in my particular app? How is the braking power vs the pedal effort? Which particular master are you using?
 
The raybestos # I have for a new replacement master is MC 36221. Thats the one looks nothing like original. Found out from Raybestos that it's only available in cast iron.

Who is gonna buy it? It's looks arent original,it's not hi perf and it's not alum.

Hey Dan; Is MC 336421 cast as well?


i have disc/drum,manual and i use an aluminum 2 bolt master 15/16 bore from a 1988 manual disc/drum dakota,,,,

This sounds like a sane approach. I'll look into this part.
 
K so I have several choices avail;

MK 551 pro grade rebuild kit.
http://www.rockauto.com/catalog/moreinfo.php?pk=310331

Cheapest option and the mc is designed to work with manual disc.Has correct 1" bore but made from heavy cast iron.

88 Dak manual disc mc 15/16" bore

m body alum mc 1 1/32" bore

Those need the adaptor,which is fine I guess.
 
I dont know what the iron replacement your looking at looks like,,but the iron 67 and maybe thru 69 had a bolt holding the cap on the master if i remember correctly,,,

just because its old stock,doesnt meen its not goood,,,and get use to the made in china factor,,

i have a manual disc/drum combo on my 66, stock 1976 dart rotors/calipers 11 inch
and 11 x 2 1/4 or 2 1/2 drums, cant remember exactly,,,

i use to run the orignal 1976 iron MC.. til it crapped out,,,
then i switched to the mopar performance master,,,they had 2 choices at the time,,,15/16 bore, and i think 1 1/16 bore,,i thought i was having mc problems,,,and mopar doesnt carry the 15/16 any longer,,

i went to rock auto,,,you can cross refrence parts on that site and discover a ton of common items used on many different vehicles,,,

i discovered the 1988 dakota, manual disc/drum used a master measured in millimeters converted to inches is equal to 15/16 bore,,,it was half the price the mopar mc was when i bought it 15 years ago,,,,

i soon discovered it was not the mc i was having problems with ,,so i now have it as a spare,,,

the 15/16 bore stops my car as good as any power brake car i ever owned,,, 15/16 will push more pressure 1 1/32 will push more fluid,,you need PRESSURE to make a caliper work properly,,,and the 15/16 bore is easier on the leg to push,,,,for me its a win win,,,

i also have NO p/p valve,, i have super tall tires on the rear 33 inch tall,,and i use an adjustable valve on the rear,it take more stopping power to stop a larger dia tire then a stock tire,,after market p/p valves are much better design then an orignal type , the choice is yours,,,, your local auto parts store car hook you up,,,get a new one not reman,,,,,unless you get a life time warranty and keep your paper work,,,,
 
Great info fast and thankyou! I plan on buying the Dak master,but my parts guy is playing with research in his spare time in hopes we can find another option that may bolt on without an adaptor. Until then I will suck the weight penalty of the original cast iron master. At least I KNOW if I rebuild it I have the correct unit and it'd been built right.

Yea I know china crap is here to stay.

I do have the original p valve for disc drum but I might just get the adjustable one. Rear tire lockup aint funny!
 
needsaresto said:
The raybestos # I have for a new replacement master is MC 36221.
Click to expand...

Again, that is a drum/drum master cylinder. You said you have disc brakes, din'tchya?

only available in cast iron.
Click to expand...

Correct. There aren't any 4-bolt masters in aluminum. They're all cast iron.

Hey Dan; Is MC 336421 cast as well?
Click to expand...

Donno; the one I pointed you at is MC36412. Yes, it's cast iron.
 
if you can get a iron one, there is nothing wrong with them,,we used them for 80 years,,,,,,,,,
 
So I bought the rebuild kit today! $36 plus tax and it seems like the best plan. The pistons it came with are stainless,as are the ones in the calipers. Should help prevent sticking. I also got wheel cyls at $10 ea but thier not stainless pistons at that price!!!

My parts guy claims there are no alum master for a 88 Dak,so I said forgetaboutit.
 
Hey slantsixdan, I am doing the exact front disc brake conversion to 4" KH manual disc and I just checked RockAuto for #MC36412 and it did not come up...looks like MC36426 is the front disc/drum rear mc at least that's what i'm seeing (be nice, i married a Canadian)
 
I just put MC36412 and MC36426 in on a p/n search on RockAuto. Both come up. The 36412 is '73-'76 A-body and '76-'77 F-body and '77 M-body, disc/drum. The 36426 is '71-'72 A-body, disc/drum. Both have 1-1/32" bore. Either will work for your swap. The 36426 probably has a residual pressure valve behind the tube seat in the forward outlet (for the rear drum brakes) so might be a better pick for a pre-'73 car, though at this late date it's highly unlikely the pre-'73 original rear wheel cylinders are still present.
 
pic of 1988 dakota 2 bolt aluminium master, from the local mom and pop parts store,,,,,,,,,,,your will be fine rebuilt if its for a drum/disc
 

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