Brake lines

[erik325i]

So, to start off, here is my current brake setup:
Dual 5/8" brake master cylinders feeding my 4-piston Brembo calipers up front with stock m3 rear brakes.

I am getting ready to plumb in a Tilton brake proportioning valve, and a set of 2-piston Brembo calipers in the rear.
I need to make custom brake lines to both the proportioning valve and the rear calipers.

Where can I get the steel lines and fittings to make brake hard lines? What size lines/fittings should I use? None of the local parts stores carry metric brake lines or fittings.

The Tilton proportioning valve is offered with either Metric 10mm fittings or AN3 fittings. I guess another option is to just run all braided stainless lines with AN3 fittings.

-Erik

[PaintPro21]

all the AN fitting companies also make tons of brake lines and fittings, so earl's, goodridge, aeroquip.... they all have stuff for you to build your own line.

there are also adapters that let step up/down in size or from metric to AN. browse their catalogs and you'll be fine.

-Eddy P (we meet at a HOD event at Thunderhill once)

[etxxz]

I bought my proportioning valve through IE. they have a Wilwood one with the BMW thread/flare type. I went to a junkyard, took a bunch of very short lines from bmw.s so to have material to play with and using a 1/4" parker pipe bender i did what i had to do and voila:


click on pic
look by radiator resevoir

setup:
e36M3 front
318ti rear

you may ask why i put the regulator in the front brake line going to the ABS unit... anyone with this setup will tell you that you can lock up the front brakes with an IX booster by barely pressing on the brakes and the rear are just there for show. My car brakes like a beast now that i use front and rear effectively.

[erik325i]

all the AN fitting companies also make tons of brake lines and fittings, so earl's, goodridge, aeroquip.... they all have stuff for you to build your own line.

there are also adapters that let step up/down in size or from metric to AN. browse their catalogs and you'll be fine.

-Eddy P (we meet at a HOD event at Thunderhill once)

Thanks, I'll look through those companies again. I quickly browsed through them earlier, but didn't see anything about hard lines.

I remember you from that event. Are you still interested in a set of 1" VAC roll center spacers? I think we were talking about them at that track day. I still have them if you want them.



etxxz,
I've reused old lines on some of the brake lines for the front, but that won't work for this one. I want to locate the proportioning valve inside the cockpit, so I need to make some long lines.

Erik

[e30rcr]

When I replaced a rusted out hard brake line I ordered it from BMW, it's bend urself but comes with the fittings flared on.

[erik325i]

When I replaced a rusted out hard brake line I ordered it from BMW, it's bend urself but comes with the fittings flared on.

That is correct. This is how I was able to redo all of the brake lines up near my master cylinders. I just measured out what sizes I needed, and looked for the closest one on realoem.

That way only works for short lines. I need to redo the line that goes all the way from the rear master cylinder to inside the cabin for the proportioning valve, to the rear of the car. There is no way I'll be able to do that with precut and flared lines from BMW even if they had the lengths I need.

Erik

[e30rcr]

I'm confused Erik, why not just get the long hard line that goes from the master to the rear T fitting. It runs the length of the car and has metric fittings, you said willwood has a metric fitting option no? Run it through the interior, chop it where you want the valve and toss on a couple more fittings, re-flare, and you're set?

[e30rcr]

Also coleman racing carres a large assortment of -3 and -4 braided lines for cheap if you go that route, up to 60" for $25

Do you run the triple master setp?

[e30rcr]

Oh and I use these guys for my fittings:

http://www.hrpworld.com/index.cfm?tpc=Adapters_-_Steel_Brake__Clutch&form_cat_id=37,24,363&action=category

[Massive Lee]

Hi Erik325

Don't waste your time with the prop valve. You won't need it if you run a front 330mm kit. You have way too much front bias, and reducing rear end won't help at all. My best recommendation is to remove the stock pressure limiting valve located bnear the firewall. You wob't gain ay rear pressure at mostaround town presure, but when you will nail the grakes, rear end will have more pressure, and it will compensate a bit. But basically, while your stock M3 had 286mm rotors all around, you just increased the front brakes by 15%.

Also, the front end will have a lot of cooling capacity, while the rear will get heat soaked. Your brake pedal will become soft from overheating... at the rear.

[erik325i]

Hi Erik325

Don't waste your time with the prop valve. You won't need it if you run a front 330mm kit. You have way too much front bias, and reducing rear end won't help at all. My best recommendation is to remove the stock pressure limiting valve located bnear the firewall. You wob't gain ay rear pressure at mostaround town presure, but when you will nail the grakes, rear end will have more pressure, and it will compensate a bit. But basically, while your stock M3 had 286mm rotors all around, you just increased the front brakes by 15%.

Also, the front end will have a lot of cooling capacity, while the rear will get heat soaked. Your brake pedal will become soft from overheating... at the rear.

Thanks for the reply Lee. When I ordered my dual master cylinder setup from Mike B, he spec'd those dual 5/8" masters to work with my 330mm 4-pot Brembos and stock e30 m3 rear brakes so I figured they should be balanced now.

I figured once I fab up these 2-piston Brembos (rear calipers off an Evo) it will put too much bias on the rear brakes which is why I was going to get the adjustible prop valve.

I don't remember the piston sizes of my calipers off hand, but you still think I will have to much front bias even with the rear Brembos? I haven't yet decided yet on what rotor to run in the rear, but I'll start test fitting different rotors to see what will work the best. The stock pressure valve is coming out for sure.
Why do you think I'll overheat the rears? I didn't think the rears would be much of an issue.

Also, a little off topic, but do you happen to offer any 2-piece rotors designed to work with the Brembo GT kit?

Erik

[Massive Lee]

Hi Erik

I didn't know that you had a custom twin pedal set-up. My mistake. As for rear piston sizing, my experience with front 332 discs/1.62-1.12-11.12 pistons is that it needs rear 310 discs/1.12-1.25 pistons, or an equivalent ratio.

My concern is not that much the braking power ratio, but heat soaking that will occure at the rear because of the lack of cooling with the rear solid rotors. Per exemple, my own M3 has front 300mm x 32 discs/SL6R calipers and stock rear discs/calipers. The front has so much heat evacuating capacity that I can drive very hard (on a track, of course) but the rear discs can't keep up wit all the heat and I may get a less stiff pedal after two sessions, due the boiling fluid... at the rear. If I bleed the rear calipers, then pedal gets back to its normal firmness.

If only you could use rear ventd rotors from another car...