Hello All,

I have recently replaced all of the flexible brake lines, pads and rotors. The MC seems to be realtively new and the calipers all function. After all of this work, I am still unimpressed with the brakes on this car.

I have read the pelican article regarding the front caliper 320i upgrade. The article also suggest that the brakes in the 914-4 are not that good. No matter how hard I try I cannot lock up the fronts.

Anyone who has done this upgrade care to comment? Does it make a significant difference?

Thanks,
Dan

I've got the 320i brakes and replaced the proportioning valve with a 'T' fitting. It's an improvement but I'm not sure it's significant compared to stock brakes that are rebuilt and bled properly. But elimininating the prop. valve does give a more solid pedal.

i know there is debate on this issue, but i was told with a 19mm MC that locking up the brakes becomes an easier task than with the 17mm.

And why, pray tell, would you want to lock up your brakes? Brakes aren't working at their maximum potential if the wheels aren't turning. What you want is brakes that exert just enough force to NOT lock up the wheels at the limit of tire adhesion. Hey, maybe we could invent a system which senses individual wheel lock up, and modulates the braking pressure to that wheel to prevent it from sliding ................! We could call it "ABS"! The Cap'n

And you may be doing a lot of praying if you are able to lock em up. You have nearly no car control with locked brakes.

If you really want to lock up your brakes, get really grippy pads and super hard tires. Then you'll be able to lock up at will, have lots of wheelspin on takeoff, can skid to a stop, and won't be able to corner.

Cap'n

I was using the phrase "lock up" to convey the fact that the brakes do not seem to stop the car in what I think is a reasonable distance. The fact is, these brakes do not seem any better then the drum units on my long departed beetles.

Perhaps what I need to do is to drive another 914 and see if there is a difference. Anyone in Long Island want to lend a helping hand to determine if there is some were else I need to look (e.g. proportioning valve...)

Thanks,
Dan

Capn--the other day you got pretty hot under the collar for people giving incomplete / and / or bad advice----

Solex--with a PROPERLY operating braking system you WILL be able to lock up the fronts, and with judicious leg power get the rears to lock as well. If you cannot do this, danger is awaiting you--I would not trust your brakes until you root out the problem. The stock system as delivered, coupled with the very good pad compounds available today will give incredible braking performance from your light weight teener. With all the replacements you have done it sounds as if there is still allot of air in the system--this is not good for the obvious--for the non-obvious it drastically reduces your boiling point, which coupled by air in the system will give very dangerous if not catastrophic results--

Get a friend / significant other to help you.

This is a procedure that may take several times to accomplish. Most of the air gets trapped in the proportioning valve. On top of it is the feed line. I have gotten very good results from just loosening this fitting and letting the fluid dribble out on its own accord-i.e. no pressure on the pedal. Let a good amount dribble out, protect your paint--then with it sealed back up. Have your partner pump the brakes a few times again and hold it to the floor with all their might---then starting from pass rear, bleed at least 2 times more than when air no longer escapes, repeat for driver rear, then pass front, then driver front--remember do not let the res get low on fluid!!

Be very careful with this--brakes are the most important item on the car--as I am sure you are aware..

Hopefully all your woes are from air and air alone--good luck and report back any and all findings to pass on to others--J

QUOTE (davep @ May 16 2005, 11:23 AM)

And you may be doing a lot of praying if you are able to lock em up. You have nearly no car control with locked brakes. If you really want to lock up your brakes, get really grippy pads and super hard tires. Then you'll be able to lock up at will, have lots of wheelspin on takeoff, can skid to a stop, and won't be able to corner.

Dave--you know the cars do not have ABS--they should lock up under severe braking--did you purposely set up your system so as they will not lock under any circumstances?

J,

Thanks for the reply, I have bled the brakes many times recently and the pedal always feels solid, but I will give it another try but this time include the proportioning valve as you have suggested.

Thanks,
Dan

QUOTE (solex @ May 16 2005, 08:25 AM)

Cap'n I was using the phrase "lock up" to convey the fact that the brakes do not seem to stop the car in what I think is a reasonable distance. The fact is, these brakes do not seem any better then the drum units on my long departed beetles. Perhaps what I need to do is to drive another 914 and see if there is a difference. Anyone in Long Island want to lend a helping hand to determine if there is some were else I need to look (e.g. proportioning valve...) Thanks, Dan

I understand what you mean... I just recently put new Zimmerman rotors on front and rear, new PBR Metal Master pads all around. These don't grip nearly as well as the old pads I had.

It does seem unsafe when the car doesn't slow down as quickly as you'd like. Maybe you should try a different brand of pads? New rotors?

I will add my $.02, if I may....you have a 30+ year old car.....not telling what deferred maintenance has been done.

Go thu the system and inspect and or replace and rubber line. Look for sweating at joints, pin holes in solid lines where they contact another part.

COMPLETELY purge the fluid and replace with high quality fluid .... I like ATE blue...check caliper specs and use an agressive pad.

I also like speed bleeders.....

QUOTE (solex @ May 16 2005, 11:30 AM)

J, Thanks for the reply, I have bled the brakes many times recently and the pedal always feels solid, but I will give it another try but this time include the proportioning valve as you have suggested. Thanks, Dan

Do not be discouraged by the number of times you may have to bleed em--it took over 3 HOURS and two gallons of fluid before I finally got mine straight----if only I bled the prop valve first--now I know--I hope it all works out for you--these things can be a real bitch---

What tire combo are you running? Type and size?? What brand of pads are you running?

QUOTE (solex @ May 16 2005, 09:30 AM)

J, Thanks for the reply, I have bled the brakes many times recently and the pedal always feels solid, but I will give it another try but this time include the proportioning valve as you have suggested. Thanks, Dan

is your floorboard flexing when you press on the brakes??

if so, this area is known to get weakened due to rust and usage.....

are the pads and rotors in good shape without being glazed over?

good brand pads or did you use the cheapest no-name pad sold at the local autoparts store??

And another thing I forgot to mention--the rear caliper venting clearances----extremely important!!! if these are not to spec it will take away some pedal power, albeit a little---make sure they are set up right...J

Man, mine flexed like a cicus performer---but because the M/C I chose to use would not allow me to weld up a brace on the carrier--I welded in a 1/8th inch steel plate to the inside of the area in question--took it all out--until the rust returns that is--and I am already expecting it--

J, Mueller,

Tires are shit but have decent tread, I have old dunlops and one toyo in the rear they are 165's. I recently replaced:

- the flexible lines with factory units from Pelican
- New Zimmerman rotors all around
- New Metal Masters pads all around
- Adjusted the venting in the rears per specs
- Power bled the system with at least 2 liters of Castrol LMA

I will definitely rebleed tonight.

Thanks guys!
Dan

Even with worn out components you should still be able to get shit tires to slide!! Sounds like it is on the path to recovery-

QUOTE (solex @ May 16 2005, 08:43 AM)

J, Mueller, Tires are shit but have decent tread, I have old dunlops and one toyo in the rear they are 165's. I recently replaced: - the flexible lines with factory units from Pelican - New Zimmerman rotors all around - New Metal Masters pads all around - Adjusted the venting in the rears per specs - Power bled the system with at least 2 liters of Castrol LMA I will definitely rebleed tonight. Thanks guys! Dan

Solex, I did the same (sans the fluid change and lines [mine are braided SS]) and experience the same thing now.

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

QUOTE (jwalters @ May 16 2005, 08:29 AM)

Dave--you know the cars do not have ABS--they should lock up under severe braking--did you purposely set up your system so as they will not lock under any circumstances?

Oh yeah, the only ABS is on my Chevy.
No, I've been upgrading my brakes since the early days. 911S on the front and 914/6 on the rear. Now I have vented rotors on the rear also. However, with brake upgrades come the tire upgrades. Basically you want the tire to have more grip than the brakes. If the brakes exceed the tires, then you get lockup and slide. Everytime I get lockup, say on gravel or sand, I tend to hit something I didn't want to hit. I do like to practice on slippery surfaces just to learn where the breakaway is.

Lets face it, these cars are all about balance. That is how I got the addiction. I pay far more attention to tires and brakes than engine and cosmetics. A ricer I am not.

QUOTE (davep @ May 16 2005, 12:57 PM)

QUOTE (jwalters @ May 16 2005, 08:29 AM) Dave--you know the cars do not have ABS--they should lock up under severe braking--did you purposely set up your system so as they will not lock under any circumstances? Oh yeah, the only ABS is on my Chevy. No, I've been upgrading my brakes since the early days. 911S on the front and 914/6 on the rear. Now I have vented rotors on the rear also. However, with brake upgrades come the tire upgrades. Basically you want the tire to have more grip than the brakes. If the brakes exceed the tires, then you get lockup and slide. Everytime I get lockup, say on gravel or sand, I tend to hit something I didn't want to hit. I do like to practice on slippery surfaces just to learn where the breakaway is. Lets face it, these cars are all about balance. That is how I got the addiction. I pay far more attention to tires and brakes than engine and cosmetics. A ricer I am not.

Sounds really kool dude--hope I get to a point one day and do the same with my teener--J

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 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/

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.

KT

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?

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.

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...

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...

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

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)

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.

QUOTE

(and really old fluid)

again, I'm outted...

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

KT

I was wondering if you'd find this one

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...


B

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.

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. KT

Hey trek--I don't pay for my fluid-- --ooops, maybe I shoul..

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!!

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... B

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!!!

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

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

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

I try NOT too lock up brakes in my cars, but others cars are fair game..

Just kidding. Tires are expensive.


B

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

I upgraded my front brake to the 320i ....now it stop on a dime

Bee Jay, DJ... what was the condition of your 914 calipers before you switched?

I have new metal master pads, rebuilt front calipers, newish rear calipers (I think - still has fresh looking zinc plating under the red paint), new 19mm master cyl and all new rotors. Car does not stop with authority. I have bled it a few times and will do it some more - if the confidence doesn't come in - I am switching pads. Did adjust the venting clearance as well.

Pads Trav, Pads...

The stock calipers were in great shape. I still have them. I was running the stock calipers, solid cross drilled 5-lug rotors with 19mm MC. I changed to the BMW calipers, and the car stops right now. With the t replacing the proportioning valve, the fronts lock up first.
Bee Jay
Here is my car:

http://www.picturetrail.com/gallery/view?p...2754&uid=598455

Guys.....914 stock brakes are GOOD!!!!

I would go with the larger master cylinder to get a little better feel for modulating.

that said, I have metal hoses(I know), I also used porterfield r4s on all 4 corners....

If you want, I can send you a set of nearly new r4s front pads to try.

I did go to the 320i set up, but I also have a 320i. (FOR SALE CHEAP!!!!)

What I like best is the pedal travel. it gave me more (so more modulating )

I could always lock up all 4 wheels at will. 914 solid rotors need cooling at the track...this is where my problems are. I know that I brake too much. but hauling down from 100+ to around 30 mph in 150' is sure a lot of fun....those 944 turbos sure brake early!

My current set up that I am very happy with is; 320i calipers, stock rotors up front with Hawk HP+. stock rears with porterfield on r4s.

With this set up I need to adjust for a little more rear bias. Once my pads were bedded in I lock up the fronts way before the rears...

Good luck!

I would like to give the RS4's a try how would we work it out? I'm willing to try almost anything at the point.

I order a set of rebuild kits for the front calipers and am considering a 19MM, but again I do not see any leaks and the pedal feels fine.

Send me a PM with your address....I will send these off tomorrow....herb

I have stock calipers and 17mm M/C. Charlesmac can tell you this car stops REAL good. braided lines good fluid gets bled once a month. pads are the key I have no idea what the pads are but they are NOT stock. I did not like the 19mm M/C as it was too hard and took more effort to really stop the car when coming to a tight AX feature. Now I can hammer the pedal and get it whoa'ed up with great confidence. My other co-driver was braking too early because he wasn't aware of the seriously short stopping distance of my teener. He comments were "Holy crap this car stops GOOD"!!!! "I can get really into the gas longer and brake WAY later than the RX8" More confidence and he believes he can get the car into FTD.

I think I'm going to go back to a 17 also...the 19 isn't the 'upgrade' I thought it would be when I bought it...should have read more before I ordered it.