This site http://www.vwhelp.com/ has very good information concerning brake and brakeline installs. However, I was wondering if anyone had any additional information to do a brake pedal/brakeline install from beginning to end. Assuming the vehicle is emptied of everything, what is the process, such as:
Pedals with Single and Dual MC's (Benefits/Drawbacks)
Which Bore Size To Choose
Which Fittings To Choose
Hardline/Stainless Braid Combo vs. All Stainless Braided
Residual Pressure Valves (Are they needed and why)
Proportioning Valve
Distribution Blocks
In-Line Hydraulic Brakelight Switch
Park Locks (Are they worth it)
Ideal Tools Needed/Tricks (Tubing Benders, etc...)
Pics Of "Clean" Installs
And anything else that pertains to a pedal assembly install. Basically, how would someone do it if starting from scratch.
Any information is appreciated...
Also, here is a related thread concerning Brake Bias:
http://www.shoptalkforums.com/viewtopic.php?t=40640
**FAQ** Braking System Component Install
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DesertGuy
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**FAQ** Braking System Component Install
Last edited by DesertGuy on Sun Dec 31, 2006 10:35 am, edited 3 times in total.
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DesertGuy
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Residual Pressure Valves are used in a both front and rear brake system as follows:
2 PSI Valves - These valves are used in a disc brake system only and are required when the master cylinder is at, or below, the height of the calipers. It's purpose is to act as an anti-siphon valve preventing the brake fluid from siphoning back into the master cylinder when the brake pedal is released. Even if the master cylinder is even or slightly above the calipers, put one in anyway. If you don't and you park on a hill, fluid will siphon! These valves are cheap insurance - put them in!
NOTE: You will know if you need one of these valves if you had to pump the pedal twice to get a good pedal. See illustration for more.
10 PSI Valves - These valves are used in a drum brake system to prevent air from being ingested into the hydraulic system when you release the brake pedal. Typical wheel cylinder seals only seal when there is pressure behind them. Rapid release of the brake pedal creates a vacuum in the system which causes the seals to relax and air is ingested into the wheel cylinders. Maintaining 10 PSI in the system at all times prevents this. Some disc/drum master cylinders have 10 PSI residual pressure valves installed internally, some don't. If you're not sure, call us and we can tell you how to check. Also, some new style wheel cylinders have cup expanders which negate the need for the residual pressure valve. Either way, if you are not sure whether you have one or not, put one in. They are not cumulative and it won't hurt anything if you have two. Don't worry about brake drag, it takes roughly 75 PSI to overcome the return springs.
From This Site: http://ecihotrodbrakes.com/
2 PSI Valves - These valves are used in a disc brake system only and are required when the master cylinder is at, or below, the height of the calipers. It's purpose is to act as an anti-siphon valve preventing the brake fluid from siphoning back into the master cylinder when the brake pedal is released. Even if the master cylinder is even or slightly above the calipers, put one in anyway. If you don't and you park on a hill, fluid will siphon! These valves are cheap insurance - put them in!
NOTE: You will know if you need one of these valves if you had to pump the pedal twice to get a good pedal. See illustration for more.
10 PSI Valves - These valves are used in a drum brake system to prevent air from being ingested into the hydraulic system when you release the brake pedal. Typical wheel cylinder seals only seal when there is pressure behind them. Rapid release of the brake pedal creates a vacuum in the system which causes the seals to relax and air is ingested into the wheel cylinders. Maintaining 10 PSI in the system at all times prevents this. Some disc/drum master cylinders have 10 PSI residual pressure valves installed internally, some don't. If you're not sure, call us and we can tell you how to check. Also, some new style wheel cylinders have cup expanders which negate the need for the residual pressure valve. Either way, if you are not sure whether you have one or not, put one in. They are not cumulative and it won't hurt anything if you have two. Don't worry about brake drag, it takes roughly 75 PSI to overcome the return springs.
From This Site: http://ecihotrodbrakes.com/
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rick.d.brown
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See also:
http://www.shining-wit.net/rick/buggy/d ... index.html
Not sure it's all 100% correct but I did a fair amount of research before putting it together.
http://www.shining-wit.net/rick/buggy/d ... index.html
Not sure it's all 100% correct but I did a fair amount of research before putting it together.
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Leatherneck
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Re: **FAQ** Brake/Brakeline Install
Pedals with Single and Dual MC's (Benefits/Drawbacks)
Which Bore Size To Choose
Which Fittings To Choose
Hardline/Stainless Braid Combo vs. All Stainless Braided
Residual Pressure Valves (Are they needed and why)
Proportioning Valve
Distribution Blocks
In-Line Hydraulic Brakelight Switch
Park Locks (Are they worth it)
Ideal Tools Needed/Tricks (Tubing Benders, etc...)
Pics Of "Clean" Installs
For optimal braking, with a new set up I would go with Dual M/C, hard lines except at pivot points where stainless braided will be used, both a Residual valve even if does not seem like it was required at the time and a proporsioning valve for fine tuning brakes, different terrains can use different braking styles a park lock only if that is the only method you have of blocking it on a hill.
Which Bore Size To Choose
Which Fittings To Choose
Hardline/Stainless Braid Combo vs. All Stainless Braided
Residual Pressure Valves (Are they needed and why)
Proportioning Valve
Distribution Blocks
In-Line Hydraulic Brakelight Switch
Park Locks (Are they worth it)
Ideal Tools Needed/Tricks (Tubing Benders, etc...)
Pics Of "Clean" Installs
For optimal braking, with a new set up I would go with Dual M/C, hard lines except at pivot points where stainless braided will be used, both a Residual valve even if does not seem like it was required at the time and a proporsioning valve for fine tuning brakes, different terrains can use different braking styles a park lock only if that is the only method you have of blocking it on a hill.
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Skidmark
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I was actually talked out of going with a line lock by one of the guys at McKenzie's. He had personal experience troubleshooting a brake pressure problem on a customer's car, and after checking everything out they ended up replacing his line lock. It cured the problem, but only for three weeks and the problem came back. The customer ended up removing the line lock from the system and had no more troubles. Word from McKenzie's is they are not reliable and fail too often. Their recommendation - carry a good wheel chock in your car (if you can't put in a mechanical parking brake).
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Skidmark
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Dual master cylinders - I have a CNC pedal assembly with a balance bar and two 3/4" master cylinders. After looking at the set up more closley, and asking some shops, I found out in order to bleed the front or the rear brake system you need to remove one or the other plunger in order to bleed the opposite system. This will be a minor PITA. Mainly due to having to crawl under the steering column to get to the pedal assembly and disconnect/connect the plungers one at a time until the systems are both bled. 
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Skidmark
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Okay - laugh all you want on this one... I am NOT an artist by any stretch. This is my cheesy planning sketch on my brake system. I am running all drum brakes (for now) without a e-brake (shift shaft above tunnel).
I did not plan on any residual valves, or proportioning valve. As far as pics of a clean install, I will post what I put in the car, and I will try to keep it as clean as possible. I am starting to install some of the braided lines today, but until I decide on the residual valve thing (Thanks alot, DesertGuy!!!) I may hold off on the hard line install until I gather more information.
I did not plan on any residual valves, or proportioning valve. As far as pics of a clean install, I will post what I put in the car, and I will try to keep it as clean as possible. I am starting to install some of the braided lines today, but until I decide on the residual valve thing (Thanks alot, DesertGuy!!!) I may hold off on the hard line install until I gather more information.
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Leatherneck
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Skidmark
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Best answer - lack of info... I plan on making a few calls to some manufacturers this morning, so I will post more info as I get it... I want to get a hold of CNC first to find out if the M/C's havea built in residual valve first. If not, whether or not they recommend one and why. I do not think VW had one in their M/C or elsewhere in the system. So if I am running all stock brakes at the wheels, why would I need one? The info hunt is on... thanks to DesertGuy. And here I thought I was going to be putting stuff together in the garage today - now I will be on the phone for a few hours until I have enough info to move forward.
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Leatherneck
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I am glad you and DeserGuy brought this topic up, has been tossed around but final conclusions are vague. What wheel cylinders are your running front and back?Skidmark wrote:Best answer - lack of info... I plan on making a few calls to some manufacturers this morning, so I will post more info as I get it... I want to get a hold of CNC first to find out if the M/C's havea built in residual valve first. If not, whether or not they recommend one and why. I do not think VW had one in their M/C or elsewhere in the system. So if I am running all stock brakes at the wheels, why would I need one? The info hunt is on... thanks to DesertGuy. And here I thought I was going to be putting stuff together in the garage today - now I will be on the phone for a few hours until I have enough info to move forward.
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bajaherbie
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Leatherneck
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Skidmark
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I just got off the phone with CNC brakes... please keep in mind that the info I received is specific for my set up, not all brake set ups...
The word I got on the residual pressure valves is this - they are mainly used to reduce the pedal travel in a brake system, along with eliminating siphoning if the wheel cylinders are higher than the M/C. With stock drum brakes, using 3/4" dia. M/C's, the system will be fine without any residual pressure valves since the volumn of fluid is large enough so the pedal travel will not be that much to start with. Apparently I will have a firm pedal (ooohhhhh.... firm pedals....) Sorry. My mind started to wander... They said if the M/C diameter was smaller, like 5/8" it would be recommended to use residual pressure valves to help reduce the pedal travel. The smaller the fluid volumn, the more pedal travel you have to engage the brakes.
The main point to all of this - each braking system can have different requirements depending on the equipment being used. The best advice would be to contact the manufacturer of the equipment you are using to get technical advise. They will know what works best with their equipment.
DesertGuy - I do appreciate you bringing this up before I got into it... I am glad I got the information ahead of building my brake system.
The word I got on the residual pressure valves is this - they are mainly used to reduce the pedal travel in a brake system, along with eliminating siphoning if the wheel cylinders are higher than the M/C. With stock drum brakes, using 3/4" dia. M/C's, the system will be fine without any residual pressure valves since the volumn of fluid is large enough so the pedal travel will not be that much to start with. Apparently I will have a firm pedal (ooohhhhh.... firm pedals....) Sorry. My mind started to wander... They said if the M/C diameter was smaller, like 5/8" it would be recommended to use residual pressure valves to help reduce the pedal travel. The smaller the fluid volumn, the more pedal travel you have to engage the brakes.
The main point to all of this - each braking system can have different requirements depending on the equipment being used. The best advice would be to contact the manufacturer of the equipment you are using to get technical advise. They will know what works best with their equipment.
DesertGuy - I do appreciate you bringing this up before I got into it... I am glad I got the information ahead of building my brake system.