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Wilwood Brake Bias valve to replace FAM7821 brake limiter valve?
Created by: davedalton2
I've had one on my mini for years with no issues. All my brake lines are plummed inside and the valve is under my dash near my shifter.
check out the official website for updates!!!!! http://www.minimeetnorth.com
Working on minis gives me the opportunity to drive cars I may never own. I have driven SPIs and MPIs as well as 89/90 Cooper carbed minis. These cars have the master bolted directly to the booster. I guess the newest was a late 90s. Of course the front brakes are 8.4 and 12 or 13 inch wheels. I have just completed the brakes on my 85 1000E. With the help of several people from the board I have converted to the late brakes. Meet the speakers provided the left hand drive under dash linkage the booster and master. Smith 1380GT had the brake bias spliter and I picked up a new master cyl. and booster kit . I run 7.5 Cooper S disc and super mini fins. Having installed the last of the bits and bled the brakes yesterday I think I'm going to be very happy with this set up. Having stripped there masters and boosters I'm thinking not many of these systems are working correctly. The rear brake portion of the master seems to suffer from rust damage (all three) and when bad enough the fluid gets into the booster (two of them) and damages it. I have one car with this system that I have not serviced and mine with all new brake bits. Once back on the road I'll compare brake performance. I know the unserviced car suffers from front lock up under panic stops. Leads me to believe the rears are not doing much if anything.
Bobbie, I did about the same thing with a 79 (I think) with the wacky diagonal split drums. I did locate a nornal MS72 in it's standard location. I tossed the car around in the wet with low fuel and adjusted till I had no rear lockup. I showed the customer how to adjust it himself and sent him on his way. The last time we talked he had adjusted his rear shoes so brakes were working but no need to mess with valve.
Thanks for the fair deal Brian, That's the last part for a completely fresh brake system. Payment goes out today. If I can help you in any way just ask.
Dave, thanks for the side step. I think it's important that the guys and gals here play fair and respect each other.
Spank I just recieved the metro brakes you passed on so I can complete a car. If you need three GBs in 6 inch e mail me and we can work something out. In three years I have not stumbled on a 4th. so they must not be high on my list.
I used the Wilwood adjustable valve on the last Mini I had. Switched from dual diagonal drums to S discs. Replumbed the brake lines for front/rear split, using the twin circuit master and the Wilwood valve. It worked great.
You can see it in this picture, near the firewall
No problem, Dave, good luck. Steve- its yours if you still want it. My paypal is the same as my email address.
Thanks for the offer Brian but I'm going to pass and most likely go with something modern like the Wilwood valve or the older mini adjustable valve MS72.
I assume you are offering that to the guy who wants to replace his with adjustable. If he does go adjutable I'd use the converted to adjustable early style supplied buy all mini parts sources.
If he does not take the deal I'd like to step up if you don't mind. Other than that part everything in my system is new or newly rebuilt . I plan on handing this car off to my son when he gets ready. Four years and counting down. Thanks
If you want a new FAM7821 brake valve, I have one that I'd love to get rid of. Might be a simple replacement is all you need? Host lists it for $235. Mine is still wrapped in oily paper with all the plugs in it. I'd take $75 for it if you want it.
FWIW, I put 1/2" rear cylinders on everything. Street, track-- all of them. If I'm out of them, I put 5/8" on.
I tried to put a jegs brake bias adjuster / rear limiter on the LeMons moke (using a single bean can master 8.4 vented 4-piston metro) and It seems to be causing more problems. The moke always seems like it's a double-pumper, even with the rear adjusted up so they're dragging. Not sure I plumbed in it right, or if I'm expecting something that it doesn't offer...
On the LeMini have a dual line master and the stock 4-way proportioning valve on it and the brakes are awesome. Always. (7.5" cut down vented w/ 4-piston minispares alloy calipers). Well, except the one time the clevis pin fell out.
It's all you man. I'd try a set of 5/8 wheel cyls to balance the system before doing the bias change. My car is heavy I run a large left tank and a S right tank and keep them above 1/2 most of the time. With 3/4 cyls it's fine till tanks get low or it rains. That's with a single stage master. Now with the change to boosted brakes I'm changing the rear cyls. in hopes of getting a better balance. I have to remove the rear mounted bias valve and replace it with a tee.
The one booster that did not have fluid in it had a master with rust pits in the rear brake piston area. Being three for three I'm thinking this is a common problem.
My greatest pleasure comes from taking someone elses mini and fixing the things they thought were just mini normal.
The rears are 3/4" bores as was fitted to the later model cars (bigger is better right?). I have not rebuilt either the master or the servo but have had them off the car several times - no external sign of rust, leaking or fluid in servo. This of course does not mean that are in proper working order. Keith Calver seem to not like the FAM7821. http://www.minimania.com/web/displayID/942/ArticleV.cfm
Here is an article for the unit in a Miata but it looks relevant.
What bore size rear wheel cyls are you using? 7.5s tend to like 5/8 dia cyls. If you use 11/16 or 3/4 the rears grab in the wet or under heavy braking. I'm currently doing the same set up on my car. 7.5s on the front the all in one booster and master with a FAM 7821. Did you rebuild your booster and master? I bought three units and two had boosters full of fluid and all had rust damage in the master. Only the rear brake portion was bothered by the rust. All three were sold as working when removed. I don't think the people were miss leading me just didn't know there was problems.
I have a late model split system with the built in servo master cylinder, 7.5" "S" disks and stock drums in the rear. Has anyone replaced the FAM7821 limiter valve with a Wilwood adjustable bias valve? I assume I would need to adapt the Wilwood to metric flares? The car gets as many track days as can be afforded and I feel the rear brakes are locking up too soon under heavy braking.