Buggy Brakes

350buggy

New Member
Joined
Nov 8, 2011
Location
Mills River
On my current crawler I have a dual master cylinder Wilwood setup. This is a non boosted set up. I recently changed over from a toyota 4cylinder with a 5 speed to a chevy 350 with an automatic transmission. I am finding that in double low I cant press the brakes hard enough to stop. Before I could clutch in and stop. Now I am having to slap it in neutral to stop. I think I really need to go to a boosted system. I already have disks on all 4 corners so with a boosted system I should have plenty of stopping power. Any thoughts or suggestions on an easy way to go about this?
 
Can you turn down your idle some? When I switched from an NP208 to an Atlas 4spd in my cab truck, I was shocked at the difference in braking when in double low (5.44:1). I turned down my idle a little, and it helped some.
 
What stall torque converter are you running. You might not have enough stall and the motor is pulling through the breaks
 
what size masters are you running?
also if your running the rubber caliper hoses replace them,they are most likely ballooning with the pedal pressure
 
JRH said:
What stall torque converter are you running. You might not have enough stall and the motor is pulling through the breaks
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This. When I had rocks under my buggy w/ an 1100 stall it would pull though the brakes easy, switched to a 2100 stall and it pretty much fixed it.
 
350buggy said:
On my current crawler I have a dual master cylinder Wilwood setup. This is a non boosted set up. I recently changed over from a toyota 4cylinder with a 5 speed to a chevy 350 with an automatic transmission. I am finding that in double low I cant press the brakes hard enough to stop. Before I could clutch in and stop. Now I am having to slap it in neutral to stop. I think I really need to go to a boosted system. I already have disks on all 4 corners so with a boosted system I should have plenty of stopping power. Any thoughts or suggestions on an easy way to go about this?
Click to expand...

Everything above is good. But, what axles are you running? Stock calipers and rotors on those axles?
 
Glad to be getting so many responses! Let me see if I can knock out a bunch of the questions in one reply. The lines are all either hard steel or braided steel lines. The front axle is toyota with the ifs calipers. The rear is toyota with disk conversion using gm calipers. The torque converter is a stock converter from a 77 blazer... I have no idea what it stalls at. The previous owner of the buggy never liked the brakes even with the toyota motor and such... he figured the bore was too big on the master cylinders... I dont know what this would effect. They do have a pretty large bore but what does this change?
 
Sounds like your brake system isn't quite matched up like it needs to be. Do you know what bore your MC's are? My buddy has an 5.3 / th350 / Atlas 4.3 with 5:13's and he can stop with dual willwood MC's and in low. 1600 stall

Get your brake setup correct first, then adjust the converter if you need to. I'm afraid if you put in a high stall, you're just masking the real issue and if you're on the gas and need to stop in a panic situation, you wont be able to.
 
350buggy said:
The previous owner of the buggy never liked the brakes even with the toyota motor and such... he figured the bore was too big on the master cylinders... I dont know what this would effect. They do have a pretty large bore but what does this change?
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The larger the bore of the MC, the more force you have to apply to the brake pedal for the same line pressure.

Pressure = Force/Area

The MC should only be as large as necessary to move the required amount of fluid in the system to operate the brakes. Larger is not better.
 
Could swapping to a 5/8" bore make enough difference? I am looking and it seems like 5/8" is the smallest wilwood makes for the type of MC I have. and does anyone have a smaller MC or set of MC's they would like to Trade for dual wilwoods in the 7/8 bore. I also have a wilwood clutch master cylinder and pedal that i am not using.
 
350buggy said:
Glad to be getting so many responses! Let me see if I can knock out a bunch of the questions in one reply. The lines are all either hard steel or braided steel lines. The front axle is toyota with the ifs calipers. The rear is toyota with disk conversion using gm calipers. The torque converter is a stock converter from a 77 blazer... I have no idea what it stalls at. The previous owner of the buggy never liked the brakes even with the toyota motor and such... he figured the bore was too big on the master cylinders... I dont know what this would effect. They do have a pretty large bore but what does this change?
Click to expand...
More stall would help but you may not like the other side of more stall. Think about that before you go that direction.
My yota had the same issue. I threw everything at it, and it only got marginally better. Get the brakes wet and all bets are off!
 
WHAT IS YOU IDEAL RPMS, WHAT IS THE TRAVEL AMOUNT OF YOUR MASTERS. IF YOUR RUNNING OUT OF TRAVEL IN YOUR MASTERS BEFORE YOUR CALP'S ARE FULLY EXTENDED YOUR PEDAL WILL BE HARD BUT NOT ENOUGH PRESSURE AT THE PISTONS IN THE CALP'S DO SOME HOME WORK FIND OUT WHAT AMOUNT OF FLUID EACH CALP. USES FULLY ENGAGED, TIMES THEM. THEN FIND OUT WHAT YOUR MASTERS CAN HANDLE. LOOK AT NASCAR THEY DON'T USE POWER, CALL WILDWOOD TEC LINE AND GIVE THEM WHAT YOU HAVE AND THEY CAN HELP YOU. AND WITH A AUTOMATIC YOU SHOULDN'T HAVE TO IDLE OVER 800 RPMS IF YOU ARE YOU NEED TO DO SOME ADJ.
 
If you have access to a pressure gauge you should have 2000 psi at max pedal pressure. 1700 is ok, anything less is lacking. Smaller bores will help but take more muscle. If you have flexible brake lines anywhere other than the wheel ends, replace it with hard line. Gator pads by Wilwood are much more aggressive and will help. What size are your rotors? Being a wilwood set up, I would think the pedal geometry is getting you enough leverage.
 
I had a bit of a brainstorm last night so tell me if I am wrong or crazy. Upon further inspection I noticed that the master cylinder for the front brakes is a 7/8 bore and the one for the rear is a larger 1" bore. Best I can tell I am not running out of stroke on either before the pedal becomes too hard to depress. I think this means I have enough volume but not enough pressure. So I am wondering if I run both the front and the rear through one of the masters say run the whole system on the 1" bore would this increase in needed volume help my situation? Then I could keep which ever master cylinder worked and run a single MC rather than the dual set up? In theory is this correct?
 
That would be less volume. But, a 1" master is too large for your rear gm calipers and id bet that 7/8 is too large for a set of toy calipers. 1" is probably way small for both but if you have a proportioning valve why not try it.
 
350buggy said:
I had a bit of a brainstorm last night so tell me if I am wrong or crazy. Upon further inspection I noticed that the master cylinder for the front brakes is a 7/8 bore and the one for the rear is a larger 1" bore. Best I can tell I am not running out of stroke on either before the pedal becomes too hard to depress. I think this means I have enough volume but not enough pressure. So I am wondering if I run both the front and the rear through one of the masters say run the whole system on the 1" bore would this increase in needed volume help my situation? Then I could keep which ever master cylinder worked and run a single MC rather than the dual set up? In theory is this correct?
Click to expand...

Sounds like a good idea, and easy enough to check. Plumb both of them into the 7/8" bore MC and see what happens. If the pedal hits the floor before the brakes get 'tight', then try the 1" MC. I checked on NAPA's website, and the stock MC on an 88 Yota pickup has a 0.8125" bore.
 
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