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Need Help With My Brakes

2K views 4 replies 5 participants last post by  Cape Cod Bob 
#1 ·
I am getting ready soon to start running brake lines on my S10. I have converted it to manual brakes to do away with the power booster. I have disc brakes on front and drum brakes on the rear. I have a few questions I need answered so I only have to do this once. If anyone can help, please do.

1. The manual master cylinder has a larger reservoir in the rear than it does in the front. Is the larger reservoir for the rear (drum) brakes?

2. What size of lines do I need to run? Is the front lines smaller than the rear?

3. I have a Wilwood Proportioning valve I was told I need to install between the the master cylinder and the rear brakes because I have disc brakes on the front. Is this true?

4. I also have a 10psi residual valve. Is this for the front (disc) brakes? Can I install it straight off of the master cylinder?


I know this is alot of questions but I need to do it right the first time. Any help would be welcomed.

Thanks all
 
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#2 ·
S10 Racer said:
I am getting ready soon to start running brake lines on my S10. I have converted it to manual brakes to do away with the power booster. I have disc brakes on front and drum brakes on the rear. I have a few questions I need answered so I only have to do this once. If anyone can help, please do.

1. The manual master cylinder has a larger reservoir in the rear than it does in the front. Is the larger reservoir for the rear (drum) brakes?

The larger reservoir is for the disc brakes.

2. What size of lines do I need to run? Is the front lines smaller than the rear?

3/16" lines will work for both ends of the truck.

3. I have a Wilwood Proportioning valve I was told I need to install between the the master cylinder and the rear brakes because I have disc brakes on the front. Is this true?

Yes, you need one, but it is to balance the brake system to prevent the front brakes from locking up before the rears. You would need one regardless of the brake system on the truck, not just because you have discs on the front.

4. I also have a 10psi residual valve. Is this for the front (disc) brakes? Can I install it straight off of the master cylinder?

No, it is for the drum brake side. Yes, you can install it right off the master cylinder or anywhere in the line that goes to both wheels.


I know this is alot of questions but I need to do it right the first time. Any help would be welcomed.

Thanks all
When removing the power booster, you may need to decrease the bore of the master cylinder compared to the original. A 1" bore would be a good place to start.

Andy
 
#3 ·
S10 Racer said:
I am getting ready soon to start running brake lines on my S10. I have converted it to manual brakes to do away with the power booster. I have disc brakes on front and drum brakes on the rear. I have a few questions I need answered so I only have to do this once. If anyone can help, please do.

1. The manual master cylinder has a larger reservoir in the rear than it does in the front. Is the larger reservoir for the rear (drum) brakes?

2. What size of lines do I need to run? Is the front lines smaller than the rear?

3. I have a Wilwood Proportioning valve I was told I need to install between the the master cylinder and the rear brakes because I have disc brakes on the front. Is this true?

4. I also have a 10psi residual valve. Is this for the front (disc) brakes? Can I install it straight off of the master cylinder?


I know this is alot of questions but I need to do it right the first time. Any help would be welcomed.

Thanks all
1. Normally, front discs are fed from the rear reservoir and drums from the front reservoir.

2. Line size won't make a lot of difference on a street driver. Larger lines will help brake response on a car where the driver is on-off-on-off the brakes in a rally/road course type of car.

3. Your system will require a metering valve to the front disc brakes and a proportioning valve to the rear brakes. Both these valves are used together in a combination valve. The metering valve reduces spike pressure to the front discs to prevent dive. The proportioning valve limits pressure to the drum brakes to prevent lock-up.

4. Your system will also require a 10# residual valve in the rear brake line. This valve will retain pressure in the line to the rear so that you will have a better pedal.

I have to wonder if you know there is a difference in master cylinder bore size between power and manual brakes. If you're planning on using the same cylinder you used for power brakes, you're in for a surprise.
 
#4 ·
techinspector1 said:
1. Normally, front discs are fed from the rear reservoir and drums from the front reservoir.
I'll have to disagree with that. Most GM cars and trucks I have (and have owned over the last 35 years) had the front discs fed from the (larger) front reservoir. The right answer is that on a disc/drum master cylinder, the larger reservoir (wherever it is) must feed the discs. The reason for this is that the disc calipers make up for pad wear by having the pistons extend further out of the bore. This requires a larger reservoir to avoid sucking air. It is also why you should remove some fluid from the reservoir before compressing the piston back into the caliper when doing a brake job.
 
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