Dual Master Cylinder Installation

geordie

Founding Member
May 10, 2002
576
2
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First job on the list for the reassembly of my car is removal of the 'fruit jar' single master cylinder and installation of a dual master cylinder. The car has front disc brakes and rear drums, no power assist. The PO bought the dual master cylinder, it is a Bendix unit.
I've trawled the internet and found a couple of articles as well as I've searched this sites previous posts. Just a couple of questions remain:
1. Is it better to bench bleed the new dual master cylinder or do this in the car before the lines are connected. I've got articles which say it can be done either way.
2. How is the push rod held in the 'fruit jar' and is this difficult to remove.
3. Any other tips would be appreciated.
 
When I converted mine, I did the following:

1) Bench bleed the MC

2) mine was held in with a spring clip. I used a 1/2" extension through the push rod hole and a lot of force while the MC was in a vice to pull it out

3) good luck.
 
2.)Could you expound on that a little?


Where did you push the 1/2" extension through? Wasn't the push rod already in the push rod hole? I'm also in the process of trying to remove the stock push rod to use it in the new M/C.
 
The write up which I am referring to basically says, to remove the 'fruit jar':
1. Remove the brake fluid
2. Disconnect the brake line
3. Remove the two bolts securing it to the firewall
4. Remove the 'fruit jar' being careful to slip off the push rod boot. Leave the push rod attached to the pedal.
Does this sound right? Reading some of the threads it sounds as if the push rod want to stay in the 'fruit jar' when it is removed.
 
The write up which I am referring to basically says, to remove the 'fruit jar':
1. Remove the brake fluid
2. Disconnect the brake line
3. Remove the two bolts securing it to the firewall
4. Remove the 'fruit jar' being careful to slip off the push rod boot. Leave the push rod attached to the pedal.
Does this sound right? Reading some of the threads it sounds as if the push rod want to stay in the 'fruit jar' when it is removed.

Sounds like a workable plan, but if the push rod is spring clipped into the MC it will not come off as you planned. Some are and some are not, just be prepared. If it is spring clipped to the MC you should remove the pushrod from the brake pedal and pull it out with the MC.
 
2.)Could you expound on that a little?


Where did you push the 1/2" extension through? Wasn't the push rod already in the push rod hole? I'm also in the process of trying to remove the stock push rod to use it in the new M/C.


geordie explained this somewhat above, the "eye hole" end. It basically fits where the brake pedal support would normally. The spring clip prevents the push rod from coming out of the MC if your pedal has no other stops (also limits play). I did not replace the spring clip because my brake pedal would not extend enough to allow the push rod to come out of the new MC.
 
Dual MC Install

1) Yes, Bench bleed the MC before you install it in the car. It could get a little messy w/the brake fluid spilling out in the engine bay. Brake fluid loves to eat paint.:(
2)Push rod is held in the MC w/a clip. Once engaged, it aint coming out so be sure you push rod is the correct length.:bang:
3)Get a brake bleeder kit from Sears, Autozone or any other parts store. It is well worth the money and will save you from a major migraine:bang: :bang:
4)Use speed bleeders in all your calipers
5)When you bleed the brakes, make sure you have lots of rags under the MC to soak up any brake fluid spillage, see item #1 above.
6)Good luck.
 
Get a brake bleeder kit from Sears said:
Spent an hour and a half driving around town looking for a master cylinder brake bleeder kit yesterday evening, no luck, tried 2 Checkers stores and an Autozone. Got some blank looks. I'm going to have a look on the internet today to see if I can get a part number.

I did get 50 feet of plastic sheet from Home Depot and some low tack tape to protect the new paint.
 
You can do the same thing with a coke bottle and a piece of hose on the end of the bleeder..........

Drink the coke, add about 1" of new fluid to the bottom of the bottle, slide the hose over the bleeder valve and into the bottom of the bottle (UNDER the level of the fluid you added, not over) and get after it SLOWLY. When finished, cap up the coke bottle for easy clean up.

:Edit: most master cylinders come with the parts to bleed them inside of the box. If you had some fittings to screw into the master cylinder you certainly could bench bleed it the same way I mention.
 
Wow...............I spent about an hour on the Checkers and Autozone (both, really poor search engines:bang: ) websites, Merles and CarQuest (no part search engines:notnice: ), Summit (no master cylinder bleeders:( ), finally found one on the Napa website and ordered it online:nice: .

I pulled up Amazon, searched on 'master bleeder' and BAM!!!!! :eek: I had multiple hits. I've now added Amazon to my Automotive parts bookmarks.

Thanks for the tip CRAIGMBA.:hail2:
 
I got the old 'fruit jar ' out last night. I drained the fluid, removed the brake lines (being very careful to avoid spilling any brake fluid), removed the two bolts attaching the reservoir and withdrew it from the firewall. The push rod was not attached to the reservoir so the whole thing came out very easily. After that I removed the existing brake lines close to the firewall to create more room for the double master cylinder.
When I get my master cylinder bench bleeding kit from Napa online I'll bleed the new cylinder and install it.
So far so good.
 
Isn't the master cyl bleeding kit simply 2 plastic fittings and small hoses?

They came free w/ the last MC I got...

a pic:

0509sc_bench_02_z.jpg


(sorry it's from spr chevy...first search hit I got...):shrug:
 
If I bench bleed the MC tonight, can I install it in the car without the lines connected without fear of it leaking brake fluid all over the engine bay, while I reroute the brake lines?