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| 87m491 |
Jul 24 2023, 05:32 AM
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#1
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Member ![]() ![]() Group: Members Posts: 331 Joined: 29-July 12 From: Portland, the original! Member No.: 14,731 Region Association: North East States
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With the prospect of incoming rotten tomatoes forefront, I wade in here looking for a little BTDT.
Background, just got the 74, 2.0 back on the road after a 7 year hiatus. Over the years,, I did fuel system, brake system (19mm master(ATE) /calipers (PMB rebuilt fronts, stock rears) /rotors/hoses) engine mechanicals and cosmetics. I haven't driven the car during that time and I only had about 150 miles on it before it came off the road and memory ain't what it used to be. I did the 19mm MC many years back because it was way less expensive than the 17 and the forum feedback seemed fine. I also have a mid 80's Carrera (with turbo brakes) against which many folks relate the 19mm MC pedal feel. I like a firm pedal and the 911 is pretty easily modulated, heavy but responsive. Fast forward to this past week and some short shakedown runs. The 914 pedal is "right there" and noticeably firmer than the 911. But while being firmer, the braking is far from commensurate with pedal input. Yes, the 911 pedal is firm, but with the right effort, the car will slow/stop NOW. Been on the track with it no problem. On the 'teener, I feel like I am about to bend/break the pedal and the car seems to barely slow. No way I can lock up these brakes at any road speed, nor do I feel I could lose momentum in a hurried stop situation, even at in town speeds. I'm wondering if I have missed something or is this type of pedal feel/action is "typical" of the swap? Shamefully, I honestly can't recall if I did pads, but the rotors are spotless and look like they're getting good pad contact but would love any pad advice as well. |
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| davep |
Aug 1 2023, 06:33 PM
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#2
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914 Historian ![]() ![]() ![]() ![]() ![]() Group: Benefactors Posts: 5,362 Joined: 13-October 03 From: Burford, ON, N0E 1A0 Member No.: 1,244 Region Association: Canada |
That is way too much free play. I think spec is 1-2 mm; just enough that it is not touching.
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| 87m491 |
Aug 2 2023, 11:40 AM
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#3
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Member ![]() ![]() Group: Members Posts: 331 Joined: 29-July 12 From: Portland, the original! Member No.: 14,731 Region Association: North East States
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A quick adjustment of the push rod to ~1mm spec and as I suspected, all that did was bring the pedal "hitting a wall" a few mms closer to the driver! For all intents and purposes it seems as if the MC is frozen which I guess is possible given the length of time of non use but it was also full of fluid as the brakes were fully bled after install.
And if trully the case, amazing I had what little braking I did have. Next item will be removal of MC and bench inspect/test. That is way too much free play. I think spec is 1-2 mm; just enough that it is not touching. |
87m491 17mm vs 19mm Brake Master Cylinder, again! Jul 24 2023, 05:32 AM
914Sixer Typical response with 19mm master cylinder. Go ov... Jul 24 2023, 06:40 AM
87m491 Thanks been all through that but didn't run ac... Jul 24 2023, 07:24 AM
SirAndy Thanks been all through that but didn't run ac... Jul 24 2023, 12:17 PM
mepstein Make sure you bed the pads to the rotors. Do it ag... Jul 24 2023, 06:48 AM
87m491 Very good idea. I sourced some of the very popula... Jul 24 2023, 07:23 AM
mepstein
Very good idea. I sourced some of the very popul... Jul 24 2023, 08:34 AM
flipb I've got the 19mm and I can definitely lock th... Jul 24 2023, 06:49 AM
Shivers I had a stock system with a 19mm. I submarined my ... Jul 24 2023, 08:24 AM
MM1 Re: Porterfield R4-S brake pad OFFICIAL break-in p... Jul 24 2023, 11:28 AM
87m491 Sweet! That'll up my 20 mile per year, th... Jul 24 2023, 12:14 PM
mepstein How do you bed in the rotor if that’s new as wel... Jul 24 2023, 12:10 PM
76-914 @Eric_Shea Shea it or don't say it! Jul 24 2023, 12:51 PM
Eric_Shea We always bed Porterfields. We're their secon... Jul 27 2023, 12:44 PM
bkrantz To get good braking response I needed to bed my R4... Jul 27 2023, 07:43 PM
Dave_Darling So, do you know you can't lock up the brakes i... Jul 28 2023, 06:01 PM
87m491 First, thanks for all the thoughts so far. As I m... Jul 29 2023, 05:58 AM
914sgofast2 What kind of brake pads are you running? If they a... Jul 28 2023, 06:15 PM
87m491
With the prospect of incoming rotten tomatoes fo... Jul 29 2023, 05:59 AM
87m491 Data point please for those w 19mm MC. What is yo... Aug 1 2023, 06:19 PM
87m491 Finally got into the hydraulics to see if the MC w... Aug 14 2023, 05:52 AM
VaccaRabite Bleed more. Use a power bleeder to pressurize the ... Aug 14 2023, 06:41 AM
87m491 Looking forward to it. As mentioned did use a pow... Aug 14 2023, 09:26 AM
87m491 I finally got back to these over the 3 day weekend... Sep 5 2023, 06:05 AM
VaccaRabite There is weirdness going on for sure.
Is the vent... Sep 5 2023, 06:59 AM
mepstein
There is weirdness going on for sure.
Is the ven... Sep 5 2023, 07:12 AM
87m491 I just wanted to give a final update for those who... Sep 5 2023, 08:42 AM
Shivers I just noticed your home state. Rotors and a lot o... Sep 5 2023, 09:15 AM
bkrantz Some speculation:
If you have a firm/hard pedal t... Sep 5 2023, 07:24 PM![]() ![]() |
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