Manual brake setup questions

D-LUX · Nov 9, 2017

Converted my trail truck to a full manual brake setup using 3/4 bore willwood master cylinders on the stock single pedal with the ratio adjusted per suggestions I've came across online.
Issue I'm having is a soft, long pedal throw and poor braking performance overall. It's stock k30 front calipers on the 60 and 10 bolt calipers on the rear 14 bolt.

Everything's bled well & I've got no leaks but the brakes suck.

Think switching to a bigger bore master would help?

Is having both masters tied together off a single pedal creating an issue?

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poolman · Nov 9, 2017

I wish I had some tech to post but I don't, my experience with manual breaks is 99% of them suck.

paradisepwoffrd · Nov 9, 2017

Can you pump the pedal to firm them up?

What lines are you running?

Is it a single master, or single pedal with 2 masters? Is there a balance bar or proportioning valve?

My bet is you don't have enough volume, assuming your lines aren't swelling. Going to a bigger master might help, but you also might just get a stiff pedal with no better braking.

If multiple pumps works, try putting residual valves in the lines.

Jeremy1 · Nov 9, 2017

I am currently working on the same set up. What pedal ratio are you using?

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Beerj · Nov 9, 2017

poolman said:
I wish I had some tech to post but I don't, my experience with manual breaks is 99% of them suck.

I might argue that your hydroboost work too well. molaugh

D-LUX said:
Converted my trail truck to a full manual brake setup using 3/4 bore willwood master cylinders on the stock single pedal with the ratio adjusted per suggestions I've came across online.
Issue I'm having is a soft, long pedal throw and poor braking performance overall. It's stock k30 front calipers on the 60 and 10 bolt calipers on the rear 14 bolt.

Everything's bled well & I've got no leaks but the brakes suck.

Think switching to a bigger bore master would help?

Is having both masters tied together off a single pedal creating an issue?

Sent from my iPhone using Tapatalk

Is the ratio good enough to allow the masters to fully compress? Sounds like you might need bigger masters or a different pedal ratio.

cushmaneaglerider · Nov 9, 2017

Replace the stock k30 brakes with the same setup you have on the rear and add 2lb residual valves inline.

gubni · Nov 10, 2017

cushmaneaglerider said:
Replace the stock k30 brakes with the same setup you have on the rear and add 2lb residual valves inline.

Yep, that's your problem. Manual brakes and stock 60 front calipers are not a good combination. Some people get it to work, but it will stop much better if you do a 3/4 ton kit on the front. I designed these kits for that reason.

$295 shipped - www.lugnut4x4.com/chevyfront

D-LUX · Nov 10, 2017

paradisepwoffrd said:
Can you pump the pedal to firm them up?

What lines are you running?

Is it a single master, or single pedal with 2 masters? Is there a balance bar or proportioning valve?

My bet is you don't have enough volume, assuming your lines aren't swelling. Going to a bigger master might help, but you also might just get a stiff pedal with no better braking.

If multiple pumps works, try putting residual valves in the lines.

Pedal doesn't firm up after pumping them...

Has braided lines from the masters to the frame, hard line tee'd for front and hardline to the rear. All the flexible lines are braided stainless so I would assume they don't swell.

Pedal ratio is 7 to 1 iirc..

It's 2 masters on a single pedal with a t-bar that actuates the masters evenly..

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D-LUX · Nov 10, 2017

cushmaneaglerider said:
Replace the stock k30 brakes with the same setup you have on the rear and add 2lb residual valves inline.

I thought having a residual valve was only for drum applications and caused the brakes to drag?

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cushmaneaglerider · Nov 10, 2017

D-LUX said:
I thought having a residual valve was only for drum applications and caused the brakes to drag?

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2lb for disc 10lb for drum
I have 3/4 master cylinders, 2lb residual valves, nylon brake lines run to -3 Kevlar lines on the axles with 1/2 ton calipers. Brakes are great. Maybe I got lucky? I am no expert.

waggener1 · Nov 12, 2017

D-LUX said:
Pedal doesn't firm up after pumping them...

Has braided lines from the masters to the frame, hard line tee'd for front and hardline to the rear. All the flexible lines are braided stainless so I would assume they don't swell.

Pedal ratio is 7 to 1 iirc..

It's 2 masters on a single pedal with a t-bar that actuates the masters evenly..

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I learned that the braided stainless steel brake hoses do in fact swell. My previous rig was a rockwell buggy with pinion brakes. I ran identical but independent brake systems front and rear... two Wilwood 7/8" master cylinders, two Wilwood 7:1 pedal assemblies, and a Wilwood 4 piston caliper on each pinion. I ran a braided stainless hose from each master cylinder all the way to its respective caliper. The brakes worked fine , and I could stop the vehicle with no problem. The rear hose was 30 - 40% longer than the front. The pedal feel on the front system always felt good and firm, but the rear was always a little "spongy" in comparison. With several attempts to ensure no air was present in the system, I'm convinced that the significantly longer lengh of braided hose in the rear allowed for more swelling resulting in the spongier pedal. It wasn't a huge problem, I just had to live with two pedals side by side that didn't feel the same. On my new rig, I'll only be running braided hose where necessary. I'll also be running only one pedal with a balance bar.