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Dual Reservoir Master Cylinder Conversion Kit
Fits 41-71 Jeep

Part # 805223-CJDUAL

New Dual Reservoir Master Cylinder Conversion Kit

This kit is an important safety upgrade from a single reservoir braking system.

The kit includes a dual reservoir master cylinder, mounting brackets and all required fasteners and instructions.

You will need a 3/8" drill bit, a double flare tool, or a buddy with a double flare tool to modify your existing brake lines. Its as simple as it gets!!!

However, you will have to run all new steel lines.

Helpful Guides and Illustrations:
Dual Reservoir Conversion Kit - Install Guide
Master Cylinder Proper Bleeding Procedure

For vehicles with original 9" drum brakes

41-45 MB
41-45 GPW
46-49 CJ-2A
49-53 CJ-3A
53-64 CJ-3B
55-66 CJ-5
50-52 M38
52-66 M38A1

Please allow 1-2 weeks for delivery.

Part # Price





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Questions & Answers

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I can not open the installation guide that is in the kit description. Is there an available link that would allow me to view the process?

Willys Jeep Parts Tech:
Email and we can get you a copy.

1. is just the bracket available? 2. This kit/ MC is for the 9" brakes only. correct? I have 11" brakes on my 61" CJ5 with XJ swing pedal/booster but wanting to go to the later CJ 11" dual MC setup in the stock location.

Willys Jeep Parts Tech:
Give us a call and we can help.

When converting to a dual master cylinder, where does the brake switch mount?

Willys Jeep Parts Tech:
Anywhere inline. It is a pressure switch.

Im wanting to do this upgrade to a 1950 Jeepster. Since no kit is available, what master cylinder and push rod work for me? I can fab my own bracketry. Thanks.

Willys Jeep Parts Tech:
We can provide you just the master cylinder out of this kit if you like. Call us toll free. Happy to help out.

I purchased the kit #805223 for a1963 cj5. the m/cylinderi received is different from the one pictured . there is no groove on the m/cylinder for the rubber bellows that covers the brake rod input. shouldn't this part be in the kit? thank you

Willys Jeep Parts Tech.:
Call us toll free and we can help out and go over for you.

Hi. I bought the 805223-CJDUAL a year ago, but I swiched my 1948 CJ2A to 11 inches drum brakes (from a1966 Brazilian Jeep pickup - front and rear). The above dual reservoir master cylinder will still work? Thanks

Willys Jeep Parts Tech:
As long as you are drum brakes, it should work.

Will this kit interfere with my pto driveshaft for the winch?

Willys Jeep Parts Tech:
No, it is in the original position of the master cylinder and should not interfere.

Why does the dual master cylinder upgrade for M38 say requires all new steel lines? Different diameter? Different pressure rating? Different fittings to master?

Willys Jeep Parts Tech:
Youll need to bend new lines to fit.

Is the brake light switch being used on this dual cylinder?

Willys Jeep Parts Tech:
Yes, that is correct.

The info says that "you will have to run all new steel lines" for the new dual cylinder. The ones on my CJ5 arent very old. I am wondering if I need to order new ones. Thanks Mark

Willys Jeep Parts Tech:
You will just need to run the line to the master cylinder, the rest will be fine.

My Jeep is a 67 CJ5 with a stock single reservoir frame mounted master cylinder. Will this kit work for me?

Willys Jeep Parts Tech:
Yes, that is correct.

I know it’s not listed, but any chance this fits a ‘64 FC-170?

Willys Jeep Parts Tech:
We have not tried to fit up to a FC.

Does this work with the complete preformed steel brakeline kit? If so which one?

Willys Jeep Parts Tech:
You will want to make your own lines to the master cylinder.

My tub is off. Found master cylinder bracket welded in. It should be bolted in, correct? Before I install two reservoir master, will have to correct. Do you sell master cylinder bracket?

Willys Jeep Parts Tech:
Email to help out on this and send us some photos so we can see.

Can this be installed without removing the tub?

Willys Jeep Parts Tech:
Yes, that is correct. You dont have to remove.

Can I still hook up my brake light switch to this or do I need a brake proportioning valve with a brake light switch? I rather not have a proportioning valve. The department of vehicles gets difficult about that

Willys Jeep Parts Tech:
This is for drum brakes and does not need a proportioning valve. Your brake light switch can go anywhere inline.

What vehicle is the master cylinder specified for and how long is it?

Willys Jeep Parts Tech:
Please see in the item description. We give a full listing and years of vehicles.

Can I buy just the mounting bracket for the dual reservoir conversion kit

Willys Jeep Parts Tech:
We may be able to help. Please email

I assume that this fits under the floor just like the original. I have a 71 CJ with a dual reservoir master cylinder sized for drum brakes. Does this provide the additional fluid volume for the disc brake setup. Do you have diagrams of the installation?

Willys Tech:
See above there is an install guide link. They go in basically the same spot as your frame mounted master cylinder.

Hallo,i have buy this kit at your services but can you give me an connecthing diagram of schema to install this?

Willys Tech:
Please see above at the install instructions link.

Hello, I purchased your master cylinder kit # 805223-CJDUAL. It will be going in a 1965 Jeep CJ5 and I am struggling with what diameter brake lines to install. I will be putting in all new hard and soft lines for the brake system, can you tell me what diameter hard line I need to get for this setup? Thank you!

Willys Jeep Parts Tech:
The stock brake lines 3/16"

I want to put this on my 1952 M38. I understand I need to run either a couple new brake lines or buy at Napa. Do you sell the needed lines? And what is the part number for the new brake light switch?

Willys Jeep Parts Tech:
The brake light switch is the same as the original, part number 647801. And for the brake lines, you just go to a local Napa and buy the pre-flarred lines and bend them to fit. Thanks

Hi; Do you have the master cylinder alone? I already have this kit but have the master cylinder bad. Thanks.

Willys Jeep Parts Tech:
Yes, we can get it for you. Email

Hello, I have a 1951 M38. I am in the process of converting the front to 11" drum brakes from 74 CJ5. So I will have 9" in the rear and 11" drum brakes in the front. This kit should work fine correct?

Willys Jeep Parts Tech:
Yes, this kit will work for your drum / drum set up.

Can you send me the video link on the installation of the master cylinder disc break conversion? I need to see the mounting of the master cylinder, the video I watched shows cutting away the old mounting system! I can’t seem to find it! My Willys is the 52 m38a1 on

Willys Jeep Parts Tech:
I'm sorry but I don't have a video on it but this guide should do the trick: Please give me a call toll free at 888-648-4923 if you have any other questions. Thanks

I have a 63 CJ5 that I have done a disc brake swap on the front. Do you offer this kit with a master cylinder that is set up for front discs and rear drums?

Willys Jeep Parts Tech:
376896 is the part number.

Will this DUAL RESERVOIR MASTER CYLINDER CONVERSION KIT work with a 1956 DJ 3A with a column shift transmission?

Willys Jeep Parts Tech:
Sorry, the bolt pattern is different for 2x4.

Will this work on a 46 cj2a with an 11in brake upgrade?

Willys Jeep Parts Tech:
Yes, this will work for a drum brake set up.

Will this unit fit a 1969 CJ5 V6?

Willys Jeep Parts Tech:
This master cylinder is only for vehicles with 9" brakes. The CJ-5 with a V6 typically had 10" brakes. Thanks

I am looking for a set up like this for 49 jeepster. Do you have any thing.

Willys Jeep Parts Tech:
Sorry, no dual reservoir kit is make for the Willys Jeepster.

I need a star washer and snap ring for my warn overdrive unit. Do you sell them separately? Thanks, Cole

Willys Jeep Parts Tech:
If you have a Warn overdrive i can probably provide but will need more information. Please email

I have 1947 CJ2A willys. will this work and if so, do i need anything else additional. Thanks

Willys Jeep Parts Tech:
Yes, this does fit. You will just need to run new lines to it. See install instructions above as well.

How do i attach the brake light sensor?

Willys Jeep Parts Tech:
You just put the brake light switch anywhere inline that has pressure.

When mine is installed, the large reservoir is toward the back, but i thought that was the front line reservoir. Are the lines supposed to cross? Or do I have it wrong and the smaller reservoir goes to he front (which doesn't make sense to me)

Willys Jeep Parts Tech:
If you can please call us toll free and we can help with install. See link above too for our install instructions in item description.

I have a 1953 CJ3B with 11' drum brakes in the rear and disc's up front. Will this work with this set up? Thanks

Willys Jeep Parts Tech:
376896 is what you would want to order for a disc/drum set up.

Do you have a dual master cylinder that would be appropriate for use with a front disc conversion on a 64 CJ5 and would a proportioning valve be needed?

Willys Jeep Parts Tech:
The proper disc brake master cylinder for the CJ-5 is part number 376896. Thanks

I own a GPW the guide states I will need a "later pedal shaft bracket riveted style" do you have a part number for this handy?

Willys Jeep Parts Tech:

I am rebuilding rear 9" drum brakes and installing new front disc brakes on 1956 CJ 5. Will this dual reservoir master brake cylinder work in this application? Do I need a proportioning valve of some kind with this set up? Thanks

Willys Jeep Parts Tech:
If you're installing disc brakes than you should use the disc brake master cylinder: Thanks

I have a two piece seat, Its like a 60 40 seat. It is 1953 truck. I dont see any 60 40 seat covers in here. Do they exist?

Willys Jeep Parts Tech:
Give us a call toll free and we can go over the options. Thanks

Why don't you offer the ( Wilwood I think ) Dual Reservoir Master Cylinder Conversion Kit that is in your 2014 catalog? Shown as item #805223-CJDual upper left hand corner on page 82.

Willys Jeep Parts Tech:
This is a more updated version. We have not had any issues with this master cylinder. Thanks!

I have a 1958 Willys CJ3-B right hand drive. I believe it was delivered from the factory in Queensland Australia as right hand drive. can you tell me if the dual master cylinder conversion will fit my vehicle ??

Willys Jeep Parts Tech:
Sorry this kit is for left hand drive only.

I have a 48 CJ2A. I have a new original master cylinder, replaced front brakes to 11in. rears are still 9in ... Still hard to stop. Will this dual master cylinder help ... or should I upgrade to 11in in the back? If so what part # do I need for the conversion?? Thanks for your time.

Willys Jeep Parts Tech:
This master cylinder should help some with that. I would also consider our disc brake conversion kits we sell as well.

Am currently installing this on my 1957 M38A1, with new break lines and cylinders, what DOT fluid type can i use now ? thanks

Willys Jeep Parts Tech:
We use DOT 3.

would this fit on a M38A1? thanks

Willys Jeep Parts Tech:
Yes, this would be the correct part for your Willys Jeep M38A1.

I have a 1953 CJ3B and want to replace the brakes with your upgrade kit, what skill level does it take? I'm very mechanically minded being a lineman for 37 years is this a job some one can get through having never done brakes before( I'm retired so time isn't a factor).......Dan

The installation itself is pretty easy, but cutting out the original MC mounting bracket so it'll fit isn't. Make sure you have the tools to cut through fairly thick metal. Once that bracket is out, it's pretty smooth from there.
Willys Tech:
Please see the install instructions. It is not too hard of a process.

works with discs in both axes?

Willys Tech:
This is for drum/drum set up. We do sell a disc dual res. master cylinder part number: 376896

I have a 1946 Jeep Willy. Can/should I use this kit on my Jeep? And what is a double flare tool?

Willys Tech:
If you have a CJ then this is the kit for you. Your local Napa will have a flare tool kit to make the lines.

Does the kit come with a dust boot for the MC pedal shaft? If not what PN do we used? Thanks

Willys Tech:
These do not require a boot.

The frame mounted master cylinder is less than desirable on my 1944 Willys army Jeep. It is difficult to get to to add fluid and seems to fail often. Is there such a thing as a conversion kit for a dash mounted master cylinder combined with an uplift brake pedal?

Willys Tech:
You should have an access cover on your floor board to add fluid to. It would be pretty hard to get a under dash to work for the Jeep.

Do you sell the kit without the master cylinder?. I have the master already.

Willys Tech:
Please call us toll free. We probably can get the brackets by themselves.

This master works on a 1956 CJ5?

Willys Tech:
Yes that is correct. It goes for all the vehicles listed above.

can I use the front and rear brake line kits that kaiser willys sells and just build the frame brake lines? If so, what do you recommend for the frame lines. I would like to buy lines that are already flared since I don't have a flaring tool.

Willys Tech:
Yes that is correct. This will not affect the front or rear lines and our kits will work. Your local NAPA sells predetermined length preflared lines. You can easily make them off of that.

What's your average ship time on this product.

Willys Tech:
We typically try to ship same day.

I have a 1960 Willys L-226 utility truck will the master cylinder kit work on this model for the dual resourvior conversation. And do you carry a sterring column shaft for this model also. Thank you.

Willys Tech:
Try part number: 805223-WODUAL for your Willys Truck. That will be the correct one.

Will this unit also fit a RHD CJ6, 1960?

Willys Tech:
These are for left hand drive vehicles only.

I'm new to this. Why do you need new brake lines? Will the brake light switch still attach? Thanks

Steven :
You can also opt for a mechanical brake light switch. There are several that have the same brake light connectors as the original
Willys Tech:
You just have to rebend your lines to this one and put an inline switch in.

Will this work on a 1967 CJ5? At the top in looks like it's covered but in the fits part it's not

Willys Tech:
Yes it should work as long as you have a frame mounted master cylinder.

What if there are no existing holes to mount the bracket for the duel master cylinder conversion kit

Willys Tech:
The kit comes with the mounting brackets.

i already have the correct master cyl, will you sell just the bracketry?

Willys Tech:
Possibly. Please call us toll free. We are more than happy to help out.

Won't work with an 11 drum upgrade?

Willys Tech:
Yes, it should work just fine if you have upgraded to 11 to the original 9.
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