View Full Version : Manual Brake Conversion ????


Smalltime
08-09-2011, 07:00 AM
I am building a drag car. This car will never see the street. I am doing a Manual Brake Conversion Kit. Can I just bypass the ABS and run all new lines with a manual prop valve in line to the rear. Any help would be great.

JL ws-6
08-09-2011, 08:03 AM
You can run all new lines, with no prop valve at all if you use the proper master. The one that Burkhart sells is set up correctly, so that the prop. valve isn't even needed.

I did this with my car.. ran all new 3/16 lines thru the entire car, one line to the back, Tee'd it on the body out to the caliper's (2 flex lines, that drop down off the body to the rear) and the front, I ran a single line down to the drivers side, put a T fiting on that, one flex line to the caliper, then ran teh 2nd along the k member over to the other side. Done deal.

The manual master, front and rear drag brakes, and redoing all the lines in the car netted about a 170 lb weight loss, all together from what was on the car stock, fwiw.

Smalltime
08-09-2011, 08:11 AM
Thank you for the information. Would you not recommend installing an adjustable prop valve to the rears for fine adjustment

BlackScreaminMachine
08-09-2011, 09:49 AM
I have personally seen JL's set up and like he said, if you buy the right Brake master, its set up correctly. Unless your running braking contest I would think its a non issue.

tee-boy
08-09-2011, 11:25 AM
Prop valve is for fine tuning. If you add one to your system, mark it with a marker, that way you can always double check that the valve didn't move b4 you make your first pass.

One you start redistributing weight, you may need a fine tune. Brake pressure sending unit, along with a guage, installed on one of the brake lines is helpful.

JL ws-6
08-09-2011, 12:17 PM
The brake pressure.. I haven't found needed unless you're footbraking for a bracket class, trying to get the right brake pressure for staging a turbo car, etc.

if you're leaving off a transbrake and don't need it to stage, it won't really do you alot of good.

The prop. valve, if you need the fine tuning then yes, by all means put one in. If you are going to drive on the street with a skinny front tire it may be a good idea too. Track only car I haven't found a need yet. I used to be able to bring my car from 142+ down quick enough so the first turnoff was almost an option..... always had PLENTY of braking room even at lvd, and their shutdown is pretty short compared to alot of places.

tee-boy
08-09-2011, 05:32 PM
I look at it like this. If you've got roughly the same brake pressure on every first pass you make b4 the fluid heats up, you know your brakes should be in good working order.

It's a safety thing. If you get past the traps, hit your brakes, and all the line pressure goes to the fronts, you'll lock up with skinny tires.

JL ws-6
08-09-2011, 05:43 PM
I've heard that before, but honestly I don't know anyone that gets on the brakes that hard... if you're going fast enough to have to do that you probably need a parachute.

Like I said, from 140+ I never got on the brakes hard, eased onto them and never, never felt like the car wouldn't stop, and it wasn't even close to light @ 3350 lbs.

tee-boy
08-09-2011, 05:49 PM
double the line pressure to the front wheels and see what happens.

JL ws-6
08-09-2011, 06:09 PM
Not sure how I would manage to do that.... :confused: If you have a manual master cyl in the car, it's going to distribute the pressure pretty even, if you double the pressure to the front you're doing the same thing to the rear, and honestly, if you are hitting the brakes that hard, something is wrong with the operator, or someone crossed the centerline in front of you in that case you may be screwed regardless if the guy comes bouncing off the wall or the like.

tee-boy
08-09-2011, 06:13 PM
you said it; not me

JL ws-6
08-09-2011, 06:14 PM
Like I said... you hammer the brakes @ the drag strip... you are doing something seriously wrong, or there's a guy coming across into your lane.. and chances are you're probably screwed.

Firehawk441
08-09-2011, 07:01 PM
I am building a drag car. This car will never see the street. I am doing a Manual Brake Conversion Kit. Can I just bypass the ABS and run all new lines with a manual prop valve in line to the rear. Any help would be great.

If you use the Strange Master cylinder that Burkhart sells, a manual prop valve isn't needed but can be installed if you feel it to be necessary. I don't use one myself and have never had an issue.

tee-boy
08-09-2011, 08:06 PM
The Wilwood prop valve distributes volume/pressure b/w the front and back brakes. It only has one inlet and one outlet. Therefore any volume change will be re-routed to the other circuit.

repo
08-09-2011, 08:12 PM
the strange master is set up so it does this for you. You choose when your puting it on wich circut you want the higher pressure to.

tee-boy
08-09-2011, 08:26 PM
I forget the ideal percentage. Is it 60 to rear and 40 to fronts?

studderin
08-09-2011, 09:08 PM
the power booster only weights 6-7? pounds right?
So is the other master lighter?

minytrker
08-10-2011, 01:14 AM
If you use the Strange Master cylinder that Burkhart sells, a manual prop valve isn't needed but can be installed if you feel it to be necessary. I don't use one myself and have never had an issue.


Same here....never have a stopping issue and no prop valve either.

Smalltime
08-11-2011, 09:57 AM
the power booster only weights 6-7? pounds right?
So is the other master lighter?

Mine is lighter. But it is not about it being lighter as much as it is a vacum issues with me running a big cam.

sweetbmxrider
08-11-2011, 10:14 AM
The Wilwood prop valve distributes volume/pressure b/w the front and back brakes. It only has one inlet and one outlet. Therefore any volume change will be re-routed to the other circuit.

Huh? I have a Wilwood on my rear brake line so it doesn't receive full pressure from the master. The front brakes are straight to the master. I dd my car this way.

SJMMFGINC
08-13-2011, 12:48 PM
Just a bit of clarity here, the Strange master cylinder or any other master cylinder is not configured for any particular car which sets bias correctly. There is no "custom" configuration that is configured correctly for a car to setup correct line pressure and flow rate with regards to biasing.

Furthermore every car (even if you narrowed it down to just an LS1) will not need the same setup as weight distribution, brakes used, tires used suspension as well as many other criteria will change the demands of the brake system. Fluid pressure on the master cylinder is approximately equal, pressures are different between ports.

For the each car to be setup correctly is about as likely as you hitting the lottery. A proportioning valve is not necessary but if you want to take advantage of utilizing your brakes to the fullest, then I would never suggest using a kit without one.

When your brake bias is not set correctly, the car will not stop as short as it could in a controlled straight manner. The object is to have all four wheels lock around the same time during threshold situations. This does not mean stomping on the brakes....as you'll generally always lock all four wheels.

All of our kits are designed with a proportioning valve for the above reasons. If you're running a strange manual master cylinder kit like BMR or others offer, we have a specific manual master ABS delete kit that is designed to work with those master cylinders.

Steve
Mechanical Engineer
SJM

studderin
08-13-2011, 01:48 PM
http://www.markwilliams.com/braketech.aspx

sweetbmxrider
08-14-2011, 09:38 AM
http://www.markwilliams.com/braketech.aspx

Cool link. I always thought you would want to lessen the brake pressure to the fronts while on skinnies. I like how they are selling a wilwood prop valve for $60 :bang:

ctjohns
10-09-2011, 07:19 PM
I am getting ready to do this conversion on my 01 trans am soon. My question is...is everyone using the strange m/c happy? I had two of their m/c on my 8 second roadster that leaked very bad. ART replaced them with new units, same POS problems. Went to Lamb m/c and what a difference, car even stopped way easier. Just wondering if the product is any better now. Chuck