New Brakes Feel Vague Options

[rickso71]

Just installed rebuilt calipers, new brake lines and hoses. I've never driver this car ('71 1.7L) or any other 914s for that matter so don't know what the brakes should feel like. These don't do much for about 1/2 travel then get firm but not great. The rotors still have rust on them from many years of sitting so I hope brakes will get better as the rust wears off. Brakes were bled several times (I know, never enough) and rear venting clearance was set to .008".

I've read in this forum that the stock 914 brakes aren't that great. What does that mean?

[Brian Mifsud]

Check the (rear) proportioning valve. This often captures air and its hard to bleed.

Also, all the car hard lines can neck down internally with corrosion and you won't see it externally. You can end up with a 'pin-hole' sized opening which produces a tremendous pressure drop. For a complete and reliable brake restoration, replace the ALL cars hardlines also if you haven't.

[rhodyguy]

new pads? did you have the rotors turned? spring for a set of speedbleeders and save yourself some time and brake fluid.

k

[Maltese Falcon]

I would of definitely had those rotors cleaned up "While you were down there". What kind of hoses, OE ,SS braided ? I'd bleed all of that old dark fluid outta there (IMG:http://www.914world.com/bbs2/html/emoticons/blink.gif)
Brake feel on a 914 ? After installing 986 4-pots w/ pagid blues all around and driving for awhile I didn't feel much difference right away. After a couple of days and some HD driving-it was a different story. Everthing "Beds in " after awhile.
Marty

[ArtechnikA]

QUOTE (rickso71 @ Aug 14 2005, 11:33 PM)

...rear venting clearance was set to .008". I've read in this forum that the stock 914 brakes aren't that great. What does that mean?

last first, it means there are uninformed people propagating uninformed hearsay.
stock 914 brakes work fine on stock-ish cars.

0.008" is 2X too big for venting clearance.

it's wrong in the spec book, which is why it's wrong in the Haynes. somebody typed the wrong number (0,2mm instead of 0,1mm) 40 years ago and the misinformation is still being used.

0,004" for rear venting clearance. that'll help.
getting the pads bedded will help too.

[meares]

ArtechnikA, not trying to be combative here but, i'm having similiar problems and i'm starting to get irritated....the clearance is @ .008........how did you hear this and are you sure!? (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) i've heard .008 so much it's burned in my brain! thanks

[rhodyguy]

when the ebrake fails to do its job, with the handle pulled way up, while parked on the hill you know the venting clearence is wrong. what gave me concern in his post was the rusty rotors and the notion he was waiting for the rust to load up the pads (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif) . my guess is he didn't check the runout either. i had a set i was planning on using until the brake guy told me "nope". althought they were in "spec" pior to turning, he could have just turned them and sent me on my way. he took the time to explain about rust that penetrates and forms "hard spots" that have to be removed. he wasn't trying to sell me new compoments either. he directed me to the least exspensive place in town to find them. cheaper than the parts houses when you figure in shipping.

k

[ArtechnikA]

QUOTE (meares @ Aug 15 2005, 08:14 AM)

ArtechnikA, not trying to be combative here but, i'm having similiar problems and i'm starting to get irritated....the clearance is @ .008........how did you hear this and are you sure!?

your clearance may be 0.008" but it *should* be 0.004" (0,1mm).

factory-trained mechanic John Larson (Cap'n Krusty) has mentioned this many times - go have a search for 'venting' and see.

all the people who have changed from 0.008" to 0.004" will concur.

it was just a typo in the spec book - somebody typed a 2 when it shouldda been a 1...

[Cap'n Krusty]

QUOTE (meares @ Aug 15 2005, 04:14 AM)

ArtechnikA, not trying to be combative here but, i'm having similiar problems and i'm starting to get irritated....the clearance is @ .008........how did you hear this and are you sure!? (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) i've heard .008 so much it's burned in my brain! thanks

It is, indeed, .004". I learned that in the brake system class at P-car school in 1973. BOTH Porsche instructors at the school agreed; the book is wrong. Nearly 35 years of personal empirical evidence confirms the material taught in the class. BTW, if you choose to keep asking until you hear the answer you want, you'll find out why they call me Cap'n Krusty. LOL

[Joe Ricard]

Yup this is easy. You can NOT expect great braking with sub-standard components.
Namely the rotors are rusty, as mentioned above that crap will get in the pad and REALLY reduce the friction co-efficient.
See for yourself .008 and .004 which works for you? if .004 drags in spots then your rotor is shot anyway.
Finally pads need to be bedded into the rotor (all the pad is in catact with the rotor).

IF you think you got all the air out drive it around and then blead it again......

[Midtowner]

Rust on those rotors? Turn them or replace! Replace pads too! My car sat for 16 years with a lot of rust on the rotors. I figured a few hours of hard use would "burn" off the stuff but noooo. (IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif)

[rhodyguy]

no replies from the poster. must be (IMG:http://www.914world.com/bbs2/html/emoticons/headbang.gif) . re buying local. no long wait or forking over $ for rapid delivery. but the windshield in the jetta got "stared" on the freeway picking up the stuff. i'll claim the other "while your in there", no better time to do the new wheel bearings and races. tires are off. might as well put the konis in, install a sway bar, or hopefully just new bushings,... this is the point where the whole thing goes south and the wife starts questioning the visa card statements.

k

[rickso71]

Okay. I replaced the hoses with OE non-braided and replaced front pads which were worn to about 4mm. Rear pads had about 6mm so kept them. I didn't turn the rotors. Was going to clean them up with emory cloth but was convinced otherwise. Now that everything's installed, is it possible to remove rotors without having to bleed brakes again? Will try the .004" venting clearance.

Does the rust really embed itself in the pads and ruin them?

[bd1308]

maybe but it would be a real pain to do....I would just bleed them.

in other words, I would make sure that everything was clean and free of bubbles. your brake system is your protection...don't risk it...

[r_towle]

welcome to the dark side.

If you need anything, drop me a line.

Just south of Nashua here,,,there are a few of us around here...

Come out to the PCA autocrosses


Rich