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Brake master cylinder?
Post by heepofajeep on Sept 10, 2006, 12:27pm
Hi, my friend just bought an M715, but it does not have a master cylinder... I was wondering what would be the easiest one to replace with, [would rather NOT use the stock m715 one].
Thanks!
Re: Brake master cylinder?
Post by compexp on Sept 10, 2006, 4:04pm
I used a Cardone 10-1331, which is a dual master - used a Napa dual master cylinder adapter, plugged the back side of the proportioning valve and ran a line extension from the rears to the new master.
Works great - total cost around $20-25.
Re: Brake master cylinder?
Post by heepofajeep on Sept 11, 2006, 1:49am
Quote: <TABLE class=bordercolor cellSpacing=1 width="90%"><TBODY><TR><TD width="100%"><TABLE class=quote cellSpacing=0 cellPadding=2 width="100%"><TBODY><TR><TD width="100%">I used a Cardone 10-1331, which is a dual master - used a Napa dual master cylinder adapter, plugged the back side of the proportioning valve and ran a line extension from the rears to the new master.
Works great - total cost around $20-25.</TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>
Did the linkage from the pedal to the MC work using the stock setup? I am not familiar with Cardone, are they just a typical parts chain?-- Is the dual MC adapter @ Napa the type of part that I can just walk up to the counter & say, "i need a Dual master cylinder adapter?", or do I need to have any additional info?
Also, was this a bolt-in job, or was there any firewall mods, etc?
Sorry for all the questions, and thank you VERY much!
Re: Brake master cylinder?
Post by wrecker on Sept 11, 2006, 6:18am
I used a wagner dual cylinder. Replacement for a early 70's FSJ 3/4 ton. Buying the adapters for the mc to line and to split/T into the stock lines at the brake light switch fitting plus about three feet of tubing was very easy and less than 40 dollars. Some have used the corvette mc from 1976 I think because it was the last year for non power brakes and would push a lot of fluid. The FSJ ones will bolt right up, no mods. If you eant power brakes in the future, you'll need a longer plunger? rod. The only thing I noticed was how hard the pedal is now and some others have noticed this as well due to having to push more fluid I think was the reason. The brakes work well though. BTW the brake light fitting is directly below where the mc should be on the frame rail. Follow the lines, you'll find it. Tim Barrman had a sticky about this before the server failed, so maybe he'll have some more advice if you need it. Bill
Re: Brake master cylinder?
Post by compexp on Sept 11, 2006, 6:57am
cardone is a brand, but most places can cross that number to a bendix, whatever.
stock linkage. napa had the adapter in their adapter bins, i'll try and dig up the part number.
everything just bolted in.
i would recommend going to power if you have the stuff, or can get it cheap. holding on hills with manual brakes bites.
Re: Brake master cylinder?
Post by brute4c on Sept 11, 2006, 9:22am
This has been done by several members:
Posted by Barrman:
This was added by Spicergear:Quote:
Many people want to get rid of the stock single line master cylinder. Either for better braking or to replace a worn out stock one. Many have done this already. This post is not about arguing what might fit or power or non power. This is a swap that I have done to my truck using the following parts. The part numbers are NAPA and the prices are what I paid for them last week.
1976 Corvette non power disc/disc master cylinder: #10-1371 $23.99
30" 3/16" brake line: #813-1205 $2.49
3/16" line plug: #131 x 3 $.29
3/16" line butt connector splice: #302 X 2 $1.99
1/4" reducer from mc to 1/4 line: #7913
3/16" reducer from mc to 3/16 line: #7914
The swap involved pulling the stock master cylinder off. Bolting the Corvette one on using the stock mount and pedal push rod. (I think adding 1/2 to 1 inch to the stock rod would make the pedal have instant pressure from its rest height. Instead of the 2-3 inch travel I get now. I will add power brakes later and see no need to mess with it twice.) I used the reducer and connected the stock brake line to the port closest to the firewall on the new master cylinder.
I then disconnected the line going to the rear brakes from the distribution block that includes the brake light pressure switch. I put the plug in the block. Put the splice on the line and connect the new 30" line to it. Slightly bend it so it goes toward the master cylinder. I now had a new line sticking about 10 inches above the master cylinder. I put a loop in it the diameter of my fist and it came out right at the master cylinder. I connected it and the reducer to the master cylinder. That is it.
I did pull the lines off of the master to "bench bleed" it on the truck using the pedal. I just hooked the lines back up and had firm brakes right away. I vacuum bled the right rear wheel cylinder to get the air the 30" line contained out of the system. I can now here the brake shoe springs working when I hit the brakes with the engine off. Not so before.
The 1976 Corvette had the option of a non power brake system with disc front and rear. That means the master cylinder had to push a lot of fluid to stop the car. They have the biggest pistons of the same size front and rear without any proportioning valve that can be found nationwide. That makes them a perfect swap into our drum front and rear trucks. Spicergear figured this out years ago and the rest of us are just using his research for our benifit. Thanks Tom.
LuckyPabst wrote:Quote:
Thanks Tim. When I did my conversion I wanted the largest piston I could find that was on a cheap part and plenty of fluid. The '76 'Vette non power had that. At like $22, it a nice part. Let me add, I ran one for years and had great brakes 'til I tore up the pads in mud. Now...all that being said, we cannot discredit or ignore mechanical theory or proven facts that our own Luckypabst/Chris has brought up time and time again.
Spicergear added:Quote:
Everyone that has used that MC (that I'm aware of) have not used a residual pressure valve without any complaints.
That said, brake theory states that drum brakes require about 10 psi held in the lines to keep the brake shoes out where they need to be. Disc brakes need closer to 2 psi.
I've heard different stories about which master cylinders have built in valves and which don't so I won't go there. If you do decide you want to run them, the big aftermarket brake companies all have a version of their own and most every hi-po supplier can get them.
Chris
Quote:
Wilwood, Baer, (etc) have them. Usually in the $15-$20 dollar range. I'm going to put a set in the system I'm building for Katie's truck based on my original Corvette master cylinder...it can't hurt.
LuckyPabst added:
compexp added:Quote:
The Vette cylinder is nice and all but for me the Jeep dual cylinder was the way to go.
It bolted in place of the original, requiring ONLY the addition of the second line down to the distribution block.
It was designed to work in a large GVW truck with 4 wheel drum brakes (and endorsed by the Jeep corporation)
It was cheap at around 30 bucks new.
From the online parts list:
Wagner #F66857
Raybestos #36246
CarQuest #20-1331
A1 Cardone #A-1-10-1331
from MudAnchor #1759 5/3/99
I'd like to add the Bendix number that I used - BXH 11331
And I believe the application was early/mid 70's J-series with 8600 lb GVW and maybe dual wheels or something to that effect.
Chris
Quote:
If you use this cylinder, as I did, you will need the adapters listed in Barrman's post at the top, as well as a Napa 7913 Dual Master Cylinder Adapter - which is required to go from the 20-1331 cylinder to a standard 1/4" line. This cylinder uses a weird thread (9/16" x 18 ), and it took me 6 stops in town today to find the right adapter. the Napa 7913 works great!
rich
Re: Brake master cylinder?
Post by robsgp on Sept 11, 2006, 10:15am
I've been contemplating this upgrade also. I took the stock push rod off with the old master cylinder. Maybe I wasn't supposed to but the boot was torn and fluid had leaked down the inside. Are the rod and boot not part of the master cylinder? Is there an aftermarket one that fits? I thought pehaps Tim had found one in his quest for a longer one. ;-)
Thanks Brute for pulling all these together. I read Barrman's original, now I have hard copy.
Re: Brake master cylinder?
Post by bluesman2a on Sept 11, 2006, 10:23am
I'll second the Corvette MC. I'm running it with all-wheel discs, no residual valves... WORKS GREAT and I can lock up all four 38" tires at will.
Re: Brake master cylinder?
Post by barrman on Sept 11, 2006, 11:52am
Rob,
The push rod should stay on the pedal. I still have the stock one in use. The money has been flowing toward paint and electrical lately and I still haven't seriously looked for a Hydroboost unit. When that does happen, I will lengthen the push rod.
But, I would suggest you do what Spicer did. Remove the stock rod. Cut it in two about in the middle. Lay the two parts in a 3" piece of 3/4 or 1 inch angle iron. Seperate them 1 inch. Tack it together. Try it on the truck and see if you need more. If you do, break the welds and make it right. Otherwise, weld it all together and drive on.