Brakes, Brakes, Brakes, Experiences with 320i upgrade Options

[Air_Cooled_Nut]

Okay, motorcycles, cars & trucks should ALL be able to lock up the brakes i.e. stop the wheels from rotating. Period. Pedal modulation and thus THRESHHOLD BRAKING (braking just to the point of locking up the tires/wheels) are what a good driver uses to stop their vehicle. Tires are your #1 method for better stopping...with the side benefits of better road holding (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) When the brakes lock up you have a pretty good idea that the system is functioning as it was designed.

When you buy brake pads/shoes you NEED to read the instructions that come with them! They tell you how to bed in (break in) the pads. This is important! Improperly done (or not at all) will give you lousy braking.

Read the articles here:
http://stoptech.com/technical/

[Trekkor]

QUOTE

two gallons of fluid

C'mon, once the system is flushed, the fluid coming out is still good. Don't tell me you throw it away.

QUOTE

I'm thinking it just takes a couple-hundred miles for the pads to grip well?

Nope, my pads were spot on... immediately.
In fact, I was able to lock up the brakes out of the top of second gear into a 40 foot slide. (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif)

KT

[solex]

I cracked the top line on the proportioning valve (for at least 15-20 mins under 15 si) and bled the rears last night. I took it out for a quick spin and have notice no change in the braking. javascript:emoticon(':confused:')
smilie

I am at my wits-end with these brakes, I have never had so much trouble. There are no leaks anywhere in the system that I can see. I rechecked the lines and fittings. Where do I look next?

[GBallantine]

Here's the setup I use on my 2.0 /4 race car.

19mm master
320 fronts/ stock rears
Hawk Blues on all 4 corners
Stainless steel lines
Wilwood 570 brake fluid
brake bias controller full open

Once the pads warm up ... incredible bite. I do notice that the pedal does seem to travel a little further with 320 setup vs stock.

[CptTripps]

I'm having the EXACT SAME issues...

New 19MM master
New Pads. (I forget whos...)
New rubber lines
ALL New steel hard lines to the MC.
320s up front, stock in the back.

I'm fine with the pedel travel, but I want to be able to stop when I mash them. I've got new tires, and was expecting to get some real nice stopping power.

I bought a T for the back, we'll put that in ans see what happens...

[Air_Cooled_Nut]

solex, this is gonna suck but maybe you should swap out the master cylinder. Also, compress each caliper and have an assistant press the brake pedal so you can WATCH the pistons move. What I would do is measure the thickness of the brake pad (but not the backing plate), compress the pistons all the way (at least flush with the caliper pad landing), then have the assistant s-l-o-w-l-y press the brake and continue to do so until the pistons moves the distance you measured on the pad. Move to the next caliper. You want to make SURE that the calipers are functioning correctly.

Watching each caliper work is more time consuming and it would seem that you're not getting pressure so I would try the master cylinder swap first. Could be a bad internal seal allowing fluid to squeeze past. BTW, when you go out and test the brakes, do you check the brake fluid resevoir afterwards? Is the fluid level the same? If it drops then you have a leak (obviously), possibly a ruptured line w/in the body. I know this is a failure point for the air-cooled VW cars...after years of no brake fluid cleaning the water rusts the brake lines from the inside out and one day a stomp on the brakes pops a line... (IMG:http://www.914world.com/bbs2/html/emoticons/sad.gif)

[solex]

Toby,
Thanks for the recommendations. I was also thinking about replacing the MC as you suggested. (Any one have a good 19 MM FS?)

The likely hood of a bad caliper some were would not make sense since none of the wheels lock up, of course all of the calipers could be bad...

I did hold the pedal down and I checked each wheel while the car was on stands, I could not move any of the wheels.

Thank you,
Dan

[Eric_Shea]

Hints and clues lie within...

Solex... those brakes should "smoke" with all the things you've done. A 914 should brake on par with a 911 of the same era. I agree with one of the very first posts, the BMW kit isn't going to give you a far greater improvement over a well working 914 system. If the pedal is hard and remains hard then... it's working. I wouldn't waste time bleeding any further if you are satisfied with your pedal feel.

Trekkor - What did you say about your new pads? (they're organic BTW)

Solex - What kind of problems are you having with your "Metallic Pads"?

Metallic pads help eliminate the squeal but what they give up in noise they also give up in stopping power. They're no match for their organic counterparts. Check Trekkors "Porterfield" thread for a line on a decent set of "organic" pads (hint: get the street versions). The man is racing the piss out of a -6 conversion with stock 914 brakes (and really old fluid) (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

I think that "average" (Jurid, Textar, Pagid street) organic pads will improve your braking at this point.

Ohhh... and check that (rear) venting clearance discussed previously. You may be totally missing 30% of your brakes.

[Trekkor]

(IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif)

QUOTE

(and really old fluid)

again, I'm outted...

I'm using new Motul now, you'll be happy to know.

KT

[Eric_Shea]

I was wondering if you'd find this one (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)

[Brad Roberts]

Crap pads. If your pedal is firm.. if everything is NEW.. and the car just doesnt want to stop: you have CRAP pads. If they cost you under 30$.. you bought junk pads that wil never "warm up" or come around.

I'll get back to my 3 hours of bleeding... (IMG:http://www.914world.com/bbs2/html/emoticons/icon8.gif)


B

[Rand]

QUOTE

motorcycles, cars & trucks should ALL be able to lock up the brakes i.e. stop the wheels from rotating. Period. Pedal modulation and thus THRESHHOLD BRAKING (braking just to the point of locking up the tires/wheels) are what a good driver uses to stop their vehicle.

At the risk of making the Cap'n get all Krusty again (who was absolutely correct in his post), I have to also agree with this. Certainly you don't want to lock your wheels and slide... yes, ABS systems are designed to help prevent this. But, our cars don't have ABS and it's up to the driver to control the braking power. If you mash hard enough (read too hard) you should be able to lock the wheels, and know the feel of that threshold.

[jwalters]

QUOTE (trekkor @ May 16 2005, 11:26 PM)

QUOTE two gallons of fluid C'mon, once the system is flushed, the fluid coming out is still good. Don't tell me you throw it away. QUOTE I'm thinking it just takes a couple-hundred miles for the pads to grip well? Nope, my pads were spot on... immediately. In fact, I was able to lock up the brakes out of the top of second gear into a 40 foot slide. (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif) KT

(IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) Hey trek--I don't pay for my fluid-- (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) --ooops, maybe I shoul..(IMG:http://www.914world.com/bbs2/html/emoticons/unsure.gif)

[jwalters]

(IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) Another thing to consider is these cars are not the american lead sleds we all grew up with--with fat tires, and locked brakes on dry pavement, these cars will stop faster than stink escaping a cows ass. Read: DRY PAVEMENT

My 73 super bug with 4 wheel drum brakes and 165/80 tires would stop in an unholy short amount of DRY tarmac--enough to embarrass the most tech apt auto on the road---

Trying to modulate these babies on the dry is a waste of time-if you need to stop quickly, stomp em and slide about 60 feet / vice trying to modulate and not stopping in over 140 feet-you need to be able to panic stomp em as 99.9% of people in panic situations do anyway-it is when it is wet that you should go to a open parking lot and learn your thresholds!!

[jwalters]

QUOTE (Brad Roberts @ May 17 2005, 06:44 PM)

Crap pads. If your pedal is firm.. if everything is NEW.. and the car just doesnt want to stop: you have CRAP pads. If they cost you under 30$.. you bought junk pads that wil never "warm up" or come around. I'll get back to my 3 hours of bleeding... (IMG:http://www.914world.com/bbs2/html/emoticons/icon8.gif) B

(IMG:http://www.914world.com/bbs2/html/emoticons/dry.gif) Yea, I learned to lift the ass real high in the air to help the process--after the fact--hehe -- that was almost on par of a biatch as a 78 Caddie eldorado with a vacuum pump enhanced system--now THAT was a bitch!!!

[solex]

Brad, et al,

I bought PBR Metal Masters from Paragon and yes they were under $30.00 for a pair.

The venting clearence is per spec and the pedal travel is less then 2 1/2 inches at the top of the pedal, which I think is pretty good at least the pedal feels solid.

Dan

[Brad Roberts]

HUm..

Pedal travel is 2.5 ? With the BMW's this is probably normal. It is a little more than I like personally, but I have felt worse pedals (scary)

I have NO experience with the PBR's so I wont comment, but IF I want my cars to stand on their nose under braking.. I run aggressive pads (Porterfields/Hawks/Performance friction) I have even run Porterfields in my crew cab truck in the past to get it to stop. The factory 30$ pads SUCKED to high heaven. It is all a trade off. If you want NO dust/NO squeal.. the car wont stop when you want it too. If you want a car that leaves seatbelt marks in your shoulder when you stand on the binders... you need real pads.


B

[shawnhayes]

Having had a lot of HPDE experience with multiple cars with and without brake upgrades, on a NON-ABS vehicle, you SHOULD be able to lock up the brakes - not that you really WANT too, but the brakes should be capable of it-especially on ANYTHING but race rubber compounds.

I am actually, though, not aware that I have ever locked up the brakes on my 914, even at VIR turn one (haven't tried, but you know, I should).

Shawn

[Brad Roberts]

(IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif) I try NOT too lock up brakes in my cars, but others cars are fair game.. (IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif)

Just kidding. Tires are expensive.


B

[Bee Jay]

My $.02 worth. I upgrade to 19 mm mc and replaced the proportioning valve with a t. Still fussed and cussed about the piss poor brakes. My Vette, Fiero, hell even my 3/4 HD pickup seemed to brake better. I upgraded (ok swapped) to BMW calipers, and I am very very happy.
Bee Jay