Hello! Log in or Register   |  Help  |  Donate  |  Buy Shirts See all banner ads | Advertise on TheSamba.com  
TheSamba.com
 
Leak from new master cylinder?
Forum Index -> Type 3 Share: Facebook Twitter
Reply to topic
Print View
Quick sort: Show newest posts on top | Show oldest posts on top View previous topic :: View next topic  
Author Message
Mike313
Samba Member


Joined: September 29, 2015
Posts: 52
Location: WA
Mike313 is offline 

PostPosted: Sat Oct 03, 2015 6:22 pm    Post subject: Leak from new master cylinder? Reply with quote

I put a new master cylinder in today purchased by the P.O. back in June from napa. It's a german made ATE part, seems new but could be remanufactured. I bled the brakes, didn't see any leaks under the car, and then realized my driver floorpan was covered in brake fluid under the carpet. I checked the reservoir and as you can see in the picture one side is empty.
When I press the pedal down there's a spongy sound coming from the boot area. Is it possible this thing was defective from the factory?
I have the receipt and might contact napa, but I'm guessing 3 months later they aren't going to do much for me. Should I order a rebuild kit for it or is there something I'm missing here? Thanks for any input,

Mike

Image may have been reduced in size. Click image to view fullscreen.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
W1K1
Samba Member


Joined: March 04, 2004
Posts: 4894
Location: Southern AB
W1K1 is offline 

PostPosted: Sat Oct 03, 2015 6:28 pm    Post subject: Reply with quote

It could be the master sat on the shelf in the warehouse for years.
Just swap in new seals and you should be good
_________________
http://www.thesamba.com/vw/archives/manuals/jim_martin_engine_build.php

1973 super
1965 squareback 1500E
1971 bay window westy- subi swap
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Mike313
Samba Member


Joined: September 29, 2015
Posts: 52
Location: WA
Mike313 is offline 

PostPosted: Sat Oct 03, 2015 7:06 pm    Post subject: Reply with quote

Thanks for the reply. I decided to order a rebuild kit through rockauto. In the meantime I'll pull it out tomorrow and remove the pistons.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
raygreenwood
Samba Member


Joined: November 24, 2008
Posts: 21474
Location: Oklahoma City
raygreenwood is offline 

PostPosted: Sat Oct 03, 2015 8:45 pm    Post subject: Reply with quote

Not so fast. I agree with the diagnosis....bad it before. But before you order anything......strip
It down and make sure there are no rust pits at the outer end. If so...a rebuild kit won't help. Also measure the bore. If its a reman and hirribly oversized....a rebuild kit wont help. Ray
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
sctbrd
Samba Member


Joined: May 06, 2013
Posts: 178
Location: Moravia, Czech Republic
sctbrd is offline 

PostPosted: Sat Oct 03, 2015 8:53 pm    Post subject: Reply with quote

If the cylinder isn't too pitted a flex hone tool works great to get a nice surface.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Mike313
Samba Member


Joined: September 29, 2015
Posts: 52
Location: WA
Mike313 is offline 

PostPosted: Sat Oct 03, 2015 9:05 pm    Post subject: Reply with quote

Thanks guys. I'll take it apart tomorrow and post back.

Mike
Back to top
View user's profile Send private message Gallery Classifieds Feedback
raygreenwood
Samba Member


Joined: November 24, 2008
Posts: 21474
Location: Oklahoma City
raygreenwood is offline 

PostPosted: Sun Oct 04, 2015 7:33 am    Post subject: Reply with quote

sctbrd wrote:
If the cylinder isn't too pitted a flex hone tool works great to get a nice surface.



Yes.....it does.....but just remember it creates the wrong surface. Rubber cups are not piston rings. They dont need cross hatch pattern.

They seals will generally work on a cross hatch pattern......but not always. The rough surface texture requires more seal pressure to conform the edge of the cup to the bore. The hydraulic pressure will do that no problem........but it wears the cup seal edge out faster......and if the bore is significantly oversized they texture may prevent a perfect seal.

I agree a flex hone is the proper type of tool to remove very light pits.....howevere it needs to be about a 400 grit....and you only want to run it in a master cylinder for a few seconds using very short strokes like about 1/2". Then lap the cylinder with something like 800 to 1000 grit to remove hone marks.

If you carefully inspect brand new cylinders....they typically have no classic hone marks in them. Ray
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
Mike313
Samba Member


Joined: September 29, 2015
Posts: 52
Location: WA
Mike313 is offline 

PostPosted: Sun Oct 04, 2015 6:25 pm    Post subject: Reply with quote

Alright I pulled the master cylinder this morning, removed the boot, and much to my surprise it was bone dry inside. Then I pulled out the seats and tore my carpeting out since my floorboards were already covered in brake fluid, and spent a few hours with a scraper and wire wheel getting all of the tar board etc out. I disconnected the rear brake line and pulled it through the front of the car and after a bit of clean up the problem was obvious. The suctioning/ spongy sound I heard wasn't coming from the boot, but from this section of the rear line beneath the pedals that looks like swiss cheese. Now I need to find a replacement or make a new one.
Image may have been reduced in size. Click image to view fullscreen.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
KTPhil Premium Member
Samba Member


Joined: April 06, 2006
Posts: 33875
Location: Conejo Valley, CA
KTPhil is online now 

PostPosted: Sun Oct 04, 2015 6:32 pm    Post subject: Reply with quote

Some have fed the single-piece pipe into the car. Others have used a union and two shorter pieces.

Search the site since folks may have posted measurements and procedures.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Mike313
Samba Member


Joined: September 29, 2015
Posts: 52
Location: WA
Mike313 is offline 

PostPosted: Sun Oct 04, 2015 8:48 pm    Post subject: Reply with quote

Thanks phil,
I ordered a 1 piece length from jbugs for $11. I'll just feed it through from the front like I removed the old one.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Tram
Samba Socialist


Joined: May 02, 2003
Posts: 22697
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
Tram is offline 

PostPosted: Sun Oct 04, 2015 11:23 pm    Post subject: Reply with quote

Mike313 wrote:
Alright I pulled the master cylinder this morning, removed the boot, and much to my surprise it was bone dry inside. Then I pulled out the seats and tore my carpeting out since my floorboards were already covered in brake fluid, and spent a few hours with a scraper and wire wheel getting all of the tar board etc out. I disconnected the rear brake line and pulled it through the front of the car and after a bit of clean up the problem was obvious. The suctioning/ spongy sound I heard wasn't coming from the boot, but from this section of the rear line beneath the pedals that looks like swiss cheese. Now I need to find a replacement or make a new one.
Image may have been reduced in size. Click image to view fullscreen.


Damn. My first thought on seeing this thread was that this was the issue, but you seemed so absolutely certain it was the MC I just kept my keyboard shut... Laughing
_________________
Немає виправдання для війни! Я з Україною.

Bryan67 wrote:
Just my hands. And a little lube. No tools.


To best contact me, please use the EMAIL function in my profile
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
Mike313
Samba Member


Joined: September 29, 2015
Posts: 52
Location: WA
Mike313 is offline 

PostPosted: Mon Oct 05, 2015 6:16 am    Post subject: Reply with quote

I was absolutely certain, and believe me this is the first time in my life I've turned out to be wrong. I swear. Smile
Back to top
View user's profile Send private message Gallery Classifieds Feedback
raygreenwood
Samba Member


Joined: November 24, 2008
Posts: 21474
Location: Oklahoma City
raygreenwood is offline 

PostPosted: Mon Oct 05, 2015 6:38 am    Post subject: Reply with quote

Good catch! Ray
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
Nate M.
Samba Member


Joined: August 11, 2003
Posts: 1306
Location: Anacortes, WA U.S.A.
Nate M. is offline 

PostPosted: Mon Oct 05, 2015 9:40 am    Post subject: Reply with quote

As a general rule, when the floor in a VW is wet, it's the rear brake line that has blown. When a master cylinder leaks, you'll get fluid out the drivers side lower front-end frame horn since that's the low point drain for the hollow, double bulkhead that the MC is attached to. On a Beetle, you will get brake fluid leaking out the center, aft part of the tunnel where the drain hole is.
_________________
Regards,

Nate M.

Squarsche build
Heavy Metal Affliction feature

For heaven's sake, put a type4 and a Porsche 5-speed in there. . . It's the right thing to do!!
Back to top
View user's profile Send private message Gallery Classifieds Feedback
RHD Notch
Samba Member


Joined: April 06, 2007
Posts: 1412
Location: Joshua Tree, CA
RHD Notch is offline 

PostPosted: Sun May 29, 2016 2:17 pm    Post subject: Re: Leak from new master cylinder? Reply with quote

So, I have a similar problem to the OP and thought it best to post here rather than start a new thread.

I had the original MC in my '66 Notchback rebuilt by a reputable Samba vendor about five years ago. I also had him confirm the condition of an extra NOS '66 only single circuit disc brake MC I had (311 611 023). Five years ago the NOS MC was confirmed to be good...

Fast forward to now...my rebuilt MC developed a leak at the rear cap where the pushrod goes. It leaked fluid down the left frame horn and also into the firewall area where the dust cap of the MC is. The MC had been working fine until this leak reared up it's ugly head.

This prompted me to install my NOS MC. The NOS MC won't build any pedal pressure after bleeding...NADA. It's like waiving your hand through the air, but it doesn't leak...yet. I'm thinking after fifty years something in it dried up.

I would like to swap the plunger/pushrod cup and o-ring seal from the NOS MC (see photo: the part with the arrow next to it) to my rebuilt MC as this appears to be the part that keeps everything sealed. There is a rebuild kit in the classifieds (311 698 181B) that I've inquired on, but no word from the seller yet.

Does this sound like a viable option or should I wait and put a kit in both MC's? Thank you

Image may have been reduced in size. Click image to view fullscreen.

_________________
Lind wrote:
I am at the point where I hardly want to own anything that isn't original paint.
campingbox wrote:
I have some other projects I'd like to finish first and I want to drive this bus while I'm working on those to help stay motivated.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
raygreenwood
Samba Member


Joined: November 24, 2008
Posts: 21474
Location: Oklahoma City
raygreenwood is offline 

PostPosted: Sun May 29, 2016 2:42 pm    Post subject: Re: Leak from new master cylinder? Reply with quote

RHD Notch wrote:
So, I have a similar problem to the OP and thought it best to post here rather than start a new thread.

I had the original MC in my '66 Notchback rebuilt by a reputable Samba vendor about five years ago. I also had him confirm the condition of an extra NOS '66 only single circuit disc brake MC I had (311 611 023). Five years ago the NOS MC was confirmed to be good...

Fast forward to now...my rebuilt MC developed a leak at the rear cap where the pushrod goes. It leaked fluid down the left frame horn and also into the firewall area where the dust cap of the MC is. The MC had been working fine until this leak reared up it's ugly head.

This prompted me to install my NOS MC. The NOS MC won't build any pedal pressure after bleeding...NADA. It's like waiving your hand through the air, but it doesn't leak...yet. I'm thinking after fifty years something in it dried up.

I would like to swap the plunger/pushrod cup and o-ring seal from the NOS MC (see photo: the part with the arrow next to it) to my rebuilt MC as this appears to be the part that keeps everything sealed. There is a rebuild kit in the classifieds (311 698 181B) that I've inquired on, but no word from the seller yet.

Does this sound like a viable option or should I wait and put a kit in both MC's? Thank you

Image may have been reduced in size. Click image to view fullscreen.


Thats no surprise. NOS brake master cylinders, most NOS brake wheel cylindrs.....are scrap. Worthless....generally.....forr anything but a good rebuildable core....and even then sometimes you get corrosion between the brass flat valve and the piston faces. In that case it's only worthwhile as a core for the springs snd cylinder as long ad they have no rust on them.

The problem is that even EPDM rubber changes a little bit with time. It hardens up slightly. The rubber is actually still good....but being confined by the bore of the cylinder.....it takes on a "set". When you try to use it.....the cups do not have enough wall pressure to properly inflate with fluid.

Pretty much any cylinder on the shelf for 5 years or more is suspect.

NOS calipers do not have this problem. Its a different kind of seal and works in q different way.
Also most of the time, master cylinder and wheel cylinder rebuild KITS......do not have this problem as long as they have been properly stored so that the seals on the pistons or in the bags are not deformed over time in storage.

If you want to collect cylinders to store snd you know they are new manufacture.....pull the pistons and rubber bungs out and store in a baggy after lubbibg with brake paste. Put the cylinder in a bucket of automatic transmission fluid. I store new and good bearings and races and precision machined parts this way. They will store forever without rust.

Buy a seal kit and just rebuild your NOS cylinder and it should be fine. Ray
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
RHD Notch
Samba Member


Joined: April 06, 2007
Posts: 1412
Location: Joshua Tree, CA
RHD Notch is offline 

PostPosted: Mon May 30, 2016 6:42 pm    Post subject: Re: Leak from new master cylinder? Reply with quote

Thanks for the info. raygreenwood. I'm trying to buy a kit now. The one I need looks to be part no. 311 689 181B according to my parts book. I could really get by with the end cap plunger/seal. If push comes to shove, I'm going to use the non-leaky plunger/seal out of my NOS MC in the recently rebuilt MC. They're both Ate MC's.

It would be interesting to know if the plunger/seal out of my
311 611 023 MC is common to another VW MC...I'm pretty sure that's all I need to stop the bleeding (pun intended) and get back on the road.

Gary
_________________
Lind wrote:
I am at the point where I hardly want to own anything that isn't original paint.
campingbox wrote:
I have some other projects I'd like to finish first and I want to drive this bus while I'm working on those to help stay motivated.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
raygreenwood
Samba Member


Joined: November 24, 2008
Posts: 21474
Location: Oklahoma City
raygreenwood is offline 

PostPosted: Mon May 30, 2016 9:26 pm    Post subject: Re: Leak from new master cylinder? Reply with quote

RHD Notch wrote:
Thanks for the info. raygreenwood. I'm trying to buy a kit now. The one I need looks to be part no. 311 689 181B according to my parts book. I could really get by with the end cap plunger/seal. If push comes to shove, I'm going to use the non-leaky plunger/seal out of my NOS MC in the recently rebuilt MC. They're both Ate MC's.

It would be interesting to know if the plunger/seal out of my
311 611 023 MC is common to another VW MC...I'm pretty sure that's all I need to stop the bleeding (pun intended) and get back on the road.

Gary


Kf the outer seal is leaking....the inner seal the,same age and conditions. You have to tk3 it out anyway.....just replace them both. False economy otherwise.

Typically most of the ATE and FAG branded seals for each size are the same. You should be able to take an outer,seal and an inner seal from any kit the same diameter piston and swap them in. Buy a late model dual cir uit kit from Rockauto for a 1972 fastback for $19 and use the seals and flap valves only. Ray
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
RHD Notch
Samba Member


Joined: April 06, 2007
Posts: 1412
Location: Joshua Tree, CA
RHD Notch is offline 

PostPosted: Thu Jun 02, 2016 8:25 pm    Post subject: Re: Leak from new master cylinder? Reply with quote

Thanks for the info. raygreenwood. Here are a couple of pics from my rebuilt (5 years ago) master cylinder. The cylinder pitting is clear and the damage to the seal is also. I'm no expert, but it seems hard to believe that wasn't there when it was rebuilt. The bore still mics out to 19.05 mm. I've only used DoT5 silicone fluid which is not hygroscopic like DoT4...My brake system was dry, spotless clean and all new when I did the brakes five years ago.

I've ordered a MC rebuild kit and will attempt to use it on the NOS MC that's in the car and won't build pressure. There shouldn't be any pitting in that one as it's been sitting in a dry box

Are there any tricks to gutting one of these and installing the new seals? Thank you!

Image may have been reduced in size. Click image to view fullscreen.


Image may have been reduced in size. Click image to view fullscreen.

_________________
Lind wrote:
I am at the point where I hardly want to own anything that isn't original paint.
campingbox wrote:
I have some other projects I'd like to finish first and I want to drive this bus while I'm working on those to help stay motivated.


Last edited by RHD Notch on Fri Jun 03, 2016 8:56 pm; edited 1 time in total
Back to top
View user's profile Send private message Gallery Classifieds Feedback
raygreenwood
Samba Member


Joined: November 24, 2008
Posts: 21474
Location: Oklahoma City
raygreenwood is offline 

PostPosted: Thu Jun 02, 2016 9:23 pm    Post subject: Re: Leak from new master cylinder? Reply with quote

Nope....that IS directly caused by the DOT 5 fluid. I get tired of arguing witj the zillion people who swear they have used DOT 5 since Noah came off the ark....and naver had a single problem.

DOT five is not hygroscopic. ....true. what that means....is that it does not ABSORB fluid into itself CHEMICALLY......meaning water does not DISSOLVE into DOT5....like it does into DOT 3 or 4.
However.....moisture enters DOT5 fluid just as readily as it does DOT 3/4.

The benefit that DOT 3/4......was actually invented for.....is that when it absorbs water.....it chemically absorbs it so that it is no longer free water. It can no longer come in contact with metal and cause corossion or rust. The drawback with DOT 3/4.....is that this absorption lowers the wet boiling point. Thats the only drawback.

DOT 5.....does not chemically dissolve water into itself....but it attracts water to itself in all the usual ways.....condensation due to temperature change and dew point being the most commonn. It SUSPENDS the water......in micro bubbles since it cannot chemically absorb it. That means that the water micro bubbles when they come in contact with metal....mif they stay there long enough......will cause rust.

The addition of water bubbles in DOT 5 does not lower wet boiling point. However.....when water concentration gets high enough the micro bubbles start to conglomeraye under pressure. If the volume gets too high and temp get too high....bubble expansion or steam flash off can cause brake fade.

DOT 5 is meant for high performance, high temp systems....like aircraft and racing that see very frequent maintenace. Ray
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
Display posts from previous:   
Reply to topic    Forum Index -> Type 3 All times are Mountain Standard Time/Pacific Daylight Savings Time
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

About | Help! | Advertise | Donate | Premium Membership | Privacy/Terms of Use | Contact Us | Site Map
Copyright © 1996-2023, Everett Barnes. All Rights Reserved.
Not affiliated with or sponsored by Volkswagen of America | Forum powered by phpBB
Links to eBay or other vendor sites may be affiliate links where the site receives compensation.