Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

2 Pages V  1 2 >  
 Reply to this topicStart new topic
> Diagnose a bad master cylinder, can't bleed this thing
terrymason
post Sep 19 2006, 07:07 PM
Post #1


Member
**

Group: Members
Posts: 346
Joined: 23-November 05
From: Virginia Beach
Member No.: 5,174
a couple of days ago my front brakes ran out of fluid - I did some inspecting, and I belive that my passenger caliper is bad. I've replaced the caliper, and went about bleeding it, but I can't get fluid in the lines.

I've taken the caliper off again, and am simply trying to get brake fluid out of the end of the brake line, just before the caliper.

I've tried both pumping the brakes and using a vacum bleeder, and can't get and fluid out of the line. The level of the resovior never drops.

So what is it? I'm assuming that there isn't a leak, could I have a bad master cylinder? Do I need to somehow prime this thing?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
bd1308
post Sep 19 2006, 07:10 PM
Post #2


Sir Post-a-lot
*****

Group: Members
Posts: 8,020
Joined: 24-January 05
From: Louisville,KY
Member No.: 3,501
Shoudlnt have to--I ran out of fluid three times when I was rebuilding the brakes, and I simply poured more fluid in and pumped the brakes to get fluid back in the lines, and then did a four point bleeding.

Maybe your MC is bad? (IMG:style_emoticons/default/confused24.gif)

b
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
terrymason
post Sep 19 2006, 07:21 PM
Post #3


Member
**

Group: Members
Posts: 346
Joined: 23-November 05
From: Virginia Beach
Member No.: 5,174
That's what I'm thinking.

The way it stands now, I've removed the passenger front caliper and pretty much just have a hard line from the MC to the passenger wheel well. I should be shooting fluid all over the place everytime I pump the brakes.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
URY914
post Sep 19 2006, 08:25 PM
Post #4


I built the lightest 914 in the history of mankind.
****************************************************************************************************

Group: Members
Posts: 120,944
Joined: 3-February 03
From: Jacksonville, FL
Member No.: 222
Region Association: None
Do you feel resistance against the pedal as you pump it?

Try bleeding the caliper on the driver side. See if you get B/F out of that one.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Brew
post Sep 19 2006, 08:27 PM
Post #5


That's Captain Moron to you!
**

Group: Members
Posts: 391
Joined: 5-August 05
From: Colorado Springs
Member No.: 4,546
Or blockage in the line.(Hey, it could happen!) Does your D-side caliper work?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
terrymason
post Sep 19 2006, 08:35 PM
Post #6


Member
**

Group: Members
Posts: 346
Joined: 23-November 05
From: Virginia Beach
Member No.: 5,174
no pedal at all - it'll hit the floor just using my hand to press the pedal. I'm guessing that if I had only rear brakes I should still be able to pump them up right?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
terrymason
post Sep 19 2006, 08:37 PM
Post #7


Member
**

Group: Members
Posts: 346
Joined: 23-November 05
From: Virginia Beach
Member No.: 5,174
I'll take the driver side off tomorrow and test, but I'm thinking that I've got a bad master cylinder
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Brew
post Sep 19 2006, 08:42 PM
Post #8


That's Captain Moron to you!
**

Group: Members
Posts: 391
Joined: 5-August 05
From: Colorado Springs
Member No.: 4,546
Kinda sounds like it, but I cant see why you wouldnt be able to get fluid out with a vacuum pump?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Hammy
post Sep 19 2006, 09:45 PM
Post #9


mr. Wonderful
***

Group: Members
Posts: 1,826
Joined: 20-October 04
From: Columbia, California
Member No.: 2,978
Region Association: Northern California
QUOTE(Brew @ Sep 19 2006, 07:42 PM) *

Kinda sounds like it, but I cant see why you wouldnt be able to get fluid out with a vacuum pump?

(IMG:style_emoticons/default/agree.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
terrymason
post Sep 20 2006, 07:01 AM
Post #10


Member
**

Group: Members
Posts: 346
Joined: 23-November 05
From: Virginia Beach
Member No.: 5,174
slightly off topic - I'm looking to replace the master cylinder with a 19mm. Anyone know what year these were in the 911s? I was looking to buy local, but don't know exactly what to ask for.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Brew
post Sep 20 2006, 07:18 AM
Post #11


That's Captain Moron to you!
**

Group: Members
Posts: 391
Joined: 5-August 05
From: Colorado Springs
Member No.: 4,546
Go to the Pelican page, the P/N is easy to find. Have your local guy cross reference it.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
terrymason
post Sep 20 2006, 07:20 AM
Post #12


Member
**

Group: Members
Posts: 346
Joined: 23-November 05
From: Virginia Beach
Member No.: 5,174
doh!

Thanks, that was easy enough.

I'm just going to upgrade to a 19mm master cylinder anyway - thanks for the help guys.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
type47
post Sep 20 2006, 07:21 AM
Post #13


Viermeister
****

Group: Members
Posts: 4,254
Joined: 7-August 03
From: Vienna, VA
Member No.: 994
Region Association: MidAtlantic Region
how old are or are your flexible rubber lines original? i've read that they swell and obstruct fluid if/when old. possibly the fault?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
ws91420
post Sep 20 2006, 07:21 AM
Post #14


Yes I have one a Lensley 914
****

Group: Members
Posts: 2,063
Joined: 10-September 03
From: Ruther Glen,VA (halfway between sticks and civilization)
Member No.: 1,137
Region Association: MidAtlantic Region
Porsche part # for 19mm MC is 901 355 012 00
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
terrymason
post Sep 20 2006, 07:23 AM
Post #15


Member
**

Group: Members
Posts: 346
Joined: 23-November 05
From: Virginia Beach
Member No.: 5,174
yeah, that's possible and I'll replace them too, but I can't get over the fact that if I pump the brakes 20 or 30 times, the fluid level in the master cylinder never moves, and fluid never makes it out of the brake line (from the disconnected caliper)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
URY914
post Sep 20 2006, 07:53 AM
Post #16


I built the lightest 914 in the history of mankind.
****************************************************************************************************

Group: Members
Posts: 120,944
Joined: 3-February 03
From: Jacksonville, FL
Member No.: 222
Region Association: None
Are you SURE that the pedal rod is pushing on the M/C? There is a piece (the rod) that rotates on the pedal that actually presses on the M/C to pressurize the system.

Somethin' ain't right here. (IMG:style_emoticons/default/wacko.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
MattR
post Sep 20 2006, 08:43 AM
Post #17


Advanced Member
****

Group: Members
Posts: 3,279
Joined: 23-January 04
From: SF Bay Area
Member No.: 1,589
Region Association: Northern California
I replaced a caliper on my 912 a while back, and when it came time to bleed I had some strange problems. I ended up buying a master cylinder and the bleeding problems went away. Thats a pretty poor troubleshoot, but when all else fails, buy a mastercylinder... hah.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
bondo
post Sep 20 2006, 02:26 PM
Post #18


Practicing my perpendicular parking
****

Group: Members
Posts: 4,277
Joined: 19-April 03
From: Los Osos, CA
Member No.: 587
Region Association: Central California
If the piston is not returning fully against the stop (circilip and washer in the bore) the holes that allow fluid in from the reservoir will not get uncovered, and the master cylinder won't be able to get any fluid. This can happen from bad actuating rod adjustment, a sticking piston, or a weak return spring.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
alpha434
post Sep 20 2006, 02:51 PM
Post #19


My member number is no coincidence.
****

Group: Members
Posts: 3,154
Joined: 16-December 05
From: Denver, CO
Member No.: 5,280
Region Association: Rocky Mountains
Where do you go to get a seal kit for the 914 m.c.?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
G e o r g e
post Sep 20 2006, 03:07 PM
Post #20


Dr
***

Group: Members
Posts: 1,905
Joined: 20-September 05
From: Southern Cal
Member No.: 4,832
Region Association: None
QUOTE(alpha434 @ Sep 20 2006, 01:51 PM) *

Where do you go to get a seal kit for the 914 m.c.?


pelican has them NLA for 17mm instock for 19 mm

(IMG:style_emoticons/default/beerchug.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
« Next Oldest · 914World Garage · Next Newest »
 

2 Pages V  1 2 >
Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 

Display Mode: Standard · Switch to: Linear+ · Switch to: Outline

Track this topic · Email this topic · Print this topic · Subscribe to this forum

- Lo-Fi Version Time is now: 1st June 2024 - 02:39 AM
Invision Power Board v9.1.4 © 2024  IPS, Inc.
All rights reserved 914World.com © since 2002
914World.com is the fastest growing online 914 community!
We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ...