plumbing race brake system

[JMortensen]

I'm into plumbing the brakes, I've put it off forever because I really hate plumbing and flaring, the whole job is annoying. Only thing worse for me is electrical. Anyway, I have 4 Goodrich SS lines with -3 fittings 90* and straight, -3 adapters for the Wilwood calipers, the dual Tilton masters came with -3 fittings. I'm using 3/16" brake line, have an AN flare tool and have a hand bender. First thing I noted is that I forgot to order any T fittings, going to need a couple of those obviously.

 

Other than that the main issue that I've seen so far is that the SS brake lines don't fit in the stock locations, so no clips to hold them in place. My thought was to run the hard line to the middle of the frame rail and then hook into the brake line and use a d ring to fasten the line to the bottom of the frame rail at the outside edge. This will keep the SS line from abraiding on the frame. Is there a better way to do it? What are you others doing in this situation?

 

Second issue is regarding the SS lines. I really think I should have gotten the straight fittings on both ends, although if I do the above then I can use the 90 degree end on the frame rail side and that solves that problem.

 

Haven't decided if I'm putting the hydraulic prop valve in the car or under the hood, since I'll have the balance bar in the car. Thinking under the hood on that one.

 

Any other suggestions would be appreciated. I know with a double flare it's a good idea to chamfer the end of the hard line, so I was planning on that. I've been thinking I'll put a curly Q under the masters so that they can be pulled off the firewall without removing the hard line, but that is pretty much the only other "trick" I know to do, so any of your hard earned knowledge would be appreciated.

[johnc]

Any other suggestions would be appreciated. I know with a double flare it's a good idea to chamfer the end of the hard line, so I was planning on that. I've been thinking I'll put a curly Q under the masters so that they can be pulled off the firewall without removing the hard line, but that is pretty much the only other "trick" I know to do, so any of your hard earned knowledge would be appreciated.

 

With AN 37 degree flares you'll also want to deburr the cut ends before flaring to keep from cracking in the flare. Use a magnifying glass to inspect each flare just to make sure there's no cracking. I run the lines in the stock location on a 240Z (up in the tunnel) after cutting, grinding out the stock bracketry. I use Rivnuts or threaded inserts, a cushioned Adel clamp, and a 10/32 stainless hex head screw about every 8" along the top of the tunnel. I'll use pop rivets instead of the threaded inserts/stainless crews if the customer's budget is a bit tight. I would put the prop valve in the engine compartment right next to the MC.

 

I use welding wire as a template for the line bending. I've never done the curly Q thing under the MC except on American cars. Its purely an aesthetic thing from my perspective and I don't want my Datsun engine compartment looking like a Chevy truck.

[JMortensen]

Thanks John. Any thoughts on the SS lines? I was calling them d rings, but Adel clamps is what I have, and I have the right size to use for the SS brake hoses.

[johnc]

Thanks John. Any thoughts on the SS lines? I was calling them d rings, but Adel clamps is what I have, and I have the right size to use for the SS brake hoses.

 

I use the Copper/Nickel brake line from Fedhill USA. Its idiot proof as far as flaring is concerned so that works well for me. Its more expensive then stainless but forms easily and I'm not cussing myself as I watch a little drip come off a tight flared fitting.

[JMortensen]

I use the Copper/Nickel brake line from Fedhill USA. Its idiot proof as far as flaring is concerned so that works well for me. Its more expensive then stainless but forms easily and I'm not cussing myself as I watch a little drip come off a tight flared fitting.

I was referring to the braided SS lines. The fittings don't fit the stock Z brackets with the U shaped clips to hold them in, so I was going to clamp the braided SS lines to the outer edge of the frame rail. I think this will allow the line to move without rubbing the frame rail. I don't really see too many options here...

[johnc]

I was referring to the braided SS lines. The fittings don't fit the stock Z brackets with the U shaped clips to hold them in, so I was going to clamp the braided SS lines to the outer edge of the frame rail. I think this will allow the line to move without rubbing the frame rail. I don't really see too many options here...

 

That will work. You can also tack weld a tab on the strut tube and attach a clamp there. I usually orient the tab so the clamp and line point at the caliper and take any of the movement/bending loads off the caliper fitting on the line. Between that and the frame rail clamp, both fittings on the line should not see any flexing, just the line itself. Also helps if you toss a cone up into the wheel well.

[zcarnut]

I was referring to the braided SS lines. The fittings don't fit the stock Z brackets with the U shaped clips to hold them in...

 

Jon;

 

The Earl’s PN 640603 metric fitting I used on my SS flex lines does indeed fit into the stock location with the OEM clip.

[JMortensen]

Messed with the pedal box again today. Realized that the hole in the firewall was just a bit too small, so I had to take the box back out. Then I was thinking about the bias adjuster. Going to need a cable support, and there is nothing even remotely close to hook the cable to. So I welded on a tab about 5" long to attach the cable to. Figured I couldn't make it too close because it might prevent the cable from moving far enough to keep up with the adjuster as it slides back and forth in the pedal assy. I suppose the other option is to cut it shorter and use a too large Adel clamp so that the sleeve for the cable can move with the adjustment.

 

Pics of the pedal box with the brake masters installed (no reservoirs yet).

[clarkspeed]

Wow that pedal box looks just like the one I fabbed about 6 months ago. I also bought a laser cut backing plate from Coleman and welded it to the firewall for some additional stiffness. Even with that, you can still see the firewall move slightly when pushing hard. I ended up ty-rapping the adjuster cable off to a bracket about 8-10" away. It didn't need much.

 

As far as brake lines, I prefer the pre-made sections. I haven't had much luck getting good seals with flaring tools.

 

I mounted the prop-valve in the my cockpit along with the balance knob. Tilton has a good article the proper use of both on their website. Adjust balance knob to optimum braking. Then reduce pressure on rear brakes using prop valve as fuel is burned off. It's the best of both worlds.

[JMortensen]

The nice thing about the AN fittings is that it is just a single flare. I've done a lot of double flares over the years so I'm pretty good at that, I just hate actually getting out there and doing it. These single flares are quite a bit easier though. I'm thinking you're right and I'll put the prop valve inside the car, there won't be a passenger seat so I really don't have to worry about it getting played with unless somebody just comes along and twists it for fun (had some ******* do that to my fuel pressure regulator once).

[Kris.Is.Awesome]

All of you deleting your boosters, does this setup give you the mech advantage you need without tiring your leg out?

[JMortensen]

I did increase the pedal ratio to about 5:1. Others have done more like 6:1. You can also play with the size of the master to up the line pressure for a given amount of pedal pressure, the trade off is that a smaller master gives more pressure and more pedal travel. I've got a 3/4" and 7/8" master that were decided on a couple years ago. Hopefully it works out, if not I may have to switch masters to get where it's comfortable. If I really screwed up I may have to get another brake pedal to mod...

Edited March 29, 2010 by JMortensen

[benitoz]

Nice pedal set up, I just got done plumbing my brakelines and I will say it started out as the most anoying jobs!

first I bought stainless lines and learned real quick I can not flare it at all with your 50.00$ flare tool. so I orderd the cunnifer lines wich are soo sweet, Than I bought the master cool flare kit. This was not cheap, but oh my god it is one of my new favorite tools. This does fuel line, brake line flares, powersteering stuff for gm ect. heres a pic.

It uses a hydraulic hand pump to press and the dies are quility and dont make a ridge down the back side or make a wobly flare. I used it on stanless and it works like butter the flares almost came out better then the cunnifer brake line I couldnt beleive it.

I have 2 new rolls of extra stainless brakline Id let go for super cheap and if some one wants this flare tool Im not going to need it for a while so Id sell it cheaper then new 220.00 if anyone is interested if you do this on a regular basis I cant imagine not having this.

http://www.amazon.com/MasterCool-Universal-Hydraulic-Flaring-Tool/dp/B00063YR2I

Edited March 30, 2010 by benitoz

[clarkspeed]

That is a nice flare tool but I could buy a lot of six dollar pre-fab lines for that cost. Still wish I had it.

 

You do end up with more "foot" pressure when switching to the dual MC setup. The booster added 300-350 lbs of force. No way around it unless you change the pedal ratio. I did the math on a spreadsheet before I switched over. Nothing excessive though, could be street driven if you wanted.

 

I have 3/4F and 5/8R MC's. The stock pedal ratio is 6.75:1. I calculated the applied force on the pedal to go from 80lb to 100lb for the same line pressure I had before with a stock MC and booster. And that's about what my seat of the pants tells me. The size of the MC's you use depend a lot on the weight transfer under braking, which depends on shocks/springs. You have to try it and if the balance bar rides too far to one side, you may need to resize one.

[JMortensen]

Not sure if that's a typo, but the stock pedal ratio is 4.2:1. Also weight transfer is not altered by shocks and springs. The speed of the weight transfer changes, but weight transfer depends primarily on the CG height and the track width on lateral and the wheelbase on longitudinal.

 

From: http://www.turnfast.com/tech_handling/handling_weightxfr

 

Contrary to what you may be inclined to believe, the amount of weight transfer is not altered by springs, shocks, anti-roll bars, etc. Weight transfer is a result of inertia and momentum. These suspension components cannot change that. What these components can do is impact how much the suspension moves in response to the load change, and how quickly the load transfers to the tire contact patches.

 

The amount of weight transfer is dominated by the vehicle's weight, location of the center of gravity, wheelbase, and track, and the amount of force applied during braking, accelerating, and cornering.

 

Weight transfer is a function of the vehicle's weight and the forces acting on that weight. Reduce the weight, and ou reduce the product the of the forces involved.

 

The center of gravity is the fulcrum point through which the vehicle's weight is multiplied by dynamic forces. In particular, the higher the CG point is, the greater the effect of the forces. Reduce the CG height reduces the product of the forces and vehicle weight.

 

The longer the wheelbase and wider the track in relation to the height of the center of gravity, the more resistance the car has to weight transfer. They behave as counteracting lateral levers to the vertical lever of the center of gravity point.

 

 

[clarkspeed]

Alright Jon, now you are freaking me out. I'm going on memory here, especially since my computer was stolen last week and I lost some of my data. But I thought the ratio was 6.75 to 1. I also thought I pulled it out of a Nissan shop manual. And I thought I measured it to verify. Either way, I'm sure I used that number for my calcs. It's easy to measure, distance from pivot point to center of foot pad divided by distance from pivot point to MC push rod. My old numbers show 13.5" to pedal and 2" to push rod. Please confirm I didn't plan my brakes the same day I put the new beer fridge in the shop.

 

Yes, you are correct that brake distribution is controlled by weight, CG, track and CF. Sorry I mistated that. I meant to make a point to check where the balance bar ends up after setting the balance. If it is too far to one side, you may need to change MC size.

[JMortensen]

I'm positive it's 4.2, but I've modded mine so can't really prove it. I can show you this link though: http://www.classiczcars.com/forums/showthread.php?t=37506 and tell you that the regular Z has the 4.2 setup. Did you move the pivot, or just weld in the tube for the balance bar right where the old hole was?

[JMortensen]

Double post.

Edited March 31, 2010 by JMortensen

[clarkspeed]

I thought I put it where the old hole was. I'm going to the shop this weekend to confirm. Wish I still had pics.

[Wheeler]

If your interested I made a brake calculation spreadsheet that can help you size and balance your brake system. You may find it useful.

 

My link