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Ledbellyhead Samba Member
Joined: March 15, 2015 Posts: 12 Location: Knoxville TN
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Posted: Wed Apr 15, 2015 7:21 am Post subject: |
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Called bus depot and they said they would mail the correct ATE, and send RMA for this one... it was drop shipped. Guess I'll be another week.
I did put a new hardware pack in the back with new springs and all.
It's been bled meticulously. I may have to shim it some with the new one, may have needed it with the old, but it was an auto zone replacement and after everyone's input I'm putting the best thing I can on it. I'm also going to do the WW Porsche 944 front disc when time allows.
I'm thinking that this could be the drums being warped like Sean said, but there is absolutely no pulse in the brakes, I can see how that could cause the shoes to shift and drag. I will take them to NAPA and see if they can turn them, they do have a slightly noticeable spot when adjusting them, but not what I would have considered a problem. |
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Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
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Posted: Wed Apr 15, 2015 8:27 am Post subject: |
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For Vendor feedback. Please use the Buyer and Seller Feedback Forum.
The Bus Depot
Thank you Tcash |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Wed Apr 15, 2015 8:48 am Post subject: |
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were it me, I would jack the rear up before and after a trip to see if one or both of the rears are dragging. You can also use an infrared gun to see which is dragging and getting hot. Use the brake bleeder screw to see if releasing pressure causes it to return and stop dragging. If it does then the issue is hydraulic. If it does not then the issue is mechanical.
Also - if you are basing the dragging issue on HEARING a dragging sound, and an IR gun shows it is not getting hot from dragging then it is the drum rubbing on the backing plate and not the shoes. There are several fixes for that.
Typical drum dragging causes that I can think of:
Rubber lines rotted on the inside
weak return springs
return springs not connected correctly
blocked port on brake master _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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kreemoweet Samba Member
Joined: March 13, 2008 Posts: 3897 Location: Seattle, WA
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Posted: Wed Apr 15, 2015 10:40 am Post subject: |
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Ledbellyhead wrote: |
I could feel the gap between where it engaged the piston and when it was retracted" |
This statement makes me think you are still not understanding that the issue people mention is with the pushrod INSIDE the booster, 'cuz
there is no way to "feel" the gap that should exist between that pushrod and its seat inside the M/C piston. If you have the system
disassembled you can check if the pushrod end sticks out even the tiniest bit past the booster-M/C mounting surface. If it does, then
there will likely be problems with at least some M/C's. Different M/C brands vary somewhat in the criticality of this measurement, and quite
likely there is some variance between the front and rear brake circuits as well. We are talking about fractions of millimeters here that can
make a huge difference in brake system behavior. The better test you can make when your new M/C arrives is to see if it can be set fully onto
the booster, without the o-ring installed, without the slightest indication of "touching" anything except the mounting surface.
I have been burned several times by Bus Depot's annoying practice of dropshipping items with no notice being given, and getting the wrong parts.
Invariably, it would involve getting cheaper substitute parts instead of the part ordered and paid for. _________________ '67 bug: seized by the authorities
'68 bug: seized by the authorities
'71 kombi: not yet seized by the authorities
Stop dead photo links! Post your photos to The Samba Gallery! |
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Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
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Posted: Wed Apr 15, 2015 5:16 pm Post subject: Brake Servo (booster) master cylinder pushrod |
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To link to this post copy and paste
Code: |
[url=https://www.thesamba.com/vw/forum/viewtopic.php?p=7636413#7636413]Brake Servo (booster) master cylinder pushrod[/url] |
Brake Servo (booster) master cylinder pushrod
Note: this measurement would normally be checked with a gauge. Placed over the brake servo pushrod. Which gives you a side view of the pushrod.
Pushrod gauge
It is easier to check this measurement on the work bench.
Look down the hole in the grommet where the lower brake fluid reservoir attaches to the master cylinder and note where the plunger is located in the Equalization port.
Using a philips screwdriver actuate the plunger while looking down the reservoir hole. Note the action of the piston inside the Equalization port.
With the master cylinder attached to the brake servo. Look down the hole in the grommet and note where the plunger is located. Actuate the plunger with the brake servo connecting rod adapter.
There should be at least 1mm (.040") of free play in the connecting rod adapter before the plunger moves.
If it requires adjustment see:
Brake Servo (booster) master cylinder pushrod
Bench bleed the master cylinder and install it to the servo using a new o-ring, in preparation to install the assembly on the vehicle.
Hope it helps
Tcash
Last edited by Tcash on Wed Sep 27, 2017 9:11 am; edited 3 times in total |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Wed Apr 15, 2015 6:08 pm Post subject: |
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on late bays the rod is adjusted between the pedal and booster, unlike many cars with boosters where the rod itself is adjustable. On early models the pushrod has an adjustment. Read Bentley Brakes and Wheels 4.1. Blocking a compensating port will keep the brakes from releasing. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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Ledbellyhead Samba Member
Joined: March 15, 2015 Posts: 12 Location: Knoxville TN
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Posted: Thu Apr 16, 2015 9:42 am Post subject: |
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Tcash wrote: |
For Vendor feedback. Please use the Buyer and Seller Feedback Forum.
The Bus Depot
Thank you Tcash |
Am I being chastised for saying this? |
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kreemoweet Samba Member
Joined: March 13, 2008 Posts: 3897 Location: Seattle, WA
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Posted: Thu Apr 16, 2015 9:50 am Post subject: |
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Ledbellyhead wrote: |
Am I being chastised for saying this? |
I see not a single word of chastisement there. I am sure the post was meant to be purely informative. Many posters here do not seem to be aware of the
feedback thread, or do not realize how much more effective their remarks would be if posted in there, instead of buried in the middle of some random thread.
I am sure many vendors look at their feedback topic there, and the general samba readership is much more likely to find relevant comments there also.
Generally speaking, posters here are capable of chastizeing without leaving any doubt whatsoever about their intent. _________________ '67 bug: seized by the authorities
'68 bug: seized by the authorities
'71 kombi: not yet seized by the authorities
Stop dead photo links! Post your photos to The Samba Gallery! |
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Ledbellyhead Samba Member
Joined: March 15, 2015 Posts: 12 Location: Knoxville TN
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Posted: Thu Apr 16, 2015 9:54 am Post subject: |
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I have checked the clearance that you speak of only by removing and re-installing the master and the feeling I was referring to was almost like you could feel it seat in the piston by pressing on it from the rod, you could feel the gap inside the booster, I studied those pictures hard a year ago. I have also tried to release on the bleeder with no pressure. When the correct master gets here and I install it, we will see. I want to do one thing at a time instead of everything so I know what the problem really was.
Checking with no o-ring and then replacing is a great idea, I did not do that.
Thanks everyone for the help! |
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Ledbellyhead Samba Member
Joined: March 15, 2015 Posts: 12 Location: Knoxville TN
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Posted: Thu Apr 16, 2015 9:57 am Post subject: |
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kreemoweet wrote: |
Ledbellyhead wrote: |
Am I being chastised for saying this? |
I see not a single word of chastisement there. I am sure the post was meant to be purely informative. Many posters here do not seem to be aware of the
feedback thread, or do not realize how much more effective their remarks would be if posted in there, instead of buried in the middle of some random thread.
I am sure many vendors look at their feedback topic there, and the general samba readership is much more likely to find relevant comments there also.
Generally speaking, posters here are capable of chastizeing without leaving any doubt whatsoever about their intent. |
Okay, great, lol, thanks. Yep I've seen some harsh stuff on here.
I was just afraid I wasn't supposed to say anything bad about a vendor or something. It's true and they seem to be straightening "this" issue out in a hurry.
I really mean it, Thanks to everyone! |
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Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
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Posted: Thu Apr 16, 2015 1:07 pm Post subject: |
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No chastization here. If that's even a word.
It is only fair to both Buyer and Seller to use the Feedback Forum.
It also gives a prospective Buyer a good resource to use when deciding to do business with a seller.
No worries.
I added some information to my previous post above.^^^
Hope it helps
Tcash |
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Ledbellyhead Samba Member
Joined: March 15, 2015 Posts: 12 Location: Knoxville TN
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Posted: Thu Apr 16, 2015 7:53 pm Post subject: |
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Thanks so much Tcash, I will check using this method as soon as it gets here, I didn't realize when I installed the other how important it was until it was bled, I may be able to install it upside down without removing the booster to check with a light. Then remove and bench bleed, and install and bleed again... |
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DougB Samba Member
Joined: January 09, 2007 Posts: 1076 Location: Falls Church, Virginia, USA
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Posted: Fri Apr 17, 2015 10:24 am Post subject: |
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Tcash wrote: |
No chastization here. If that's even a word. |
It is NOW! _________________ '75 Campmobile (tin-top to SpaceRoof)
'73 Fastback
'52 BMW R67/2
'41 Zundapp KS600
'55 Puch SGS250
A very, very understanding wife |
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NOVA Bus Samba Member
Joined: April 18, 2005 Posts: 517 Location: Herndon, VA
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Posted: Fri Aug 28, 2020 2:09 pm Post subject: Re: Odd rear brake behavior |
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So just reviving this thread; I have given up on the WW "Throw you through the windshield" brake servo. It's not a good reproduction, period.
For replacement I located a well preserved used brake servo OE ATE spec for my '77 bus.
To review, the booster push rod (point) which nests into the brake manifold is NOT adjustable inside the booster itself, per Bentley the adjustment for the push rod pin can only be performed by adjusting the extension "tie-rod" link which connect from the front of the brake servo lock but to the brake pedal linkage.
Also Many posts on here regarding restoration options for original brake servos, it looks like there are still some good sources, but upwards of $200 to perform this repair. _________________ ********************************
1977 Transporter / Weekender
- GE engine, L-Jetronic w/ hyd. lifters
- Brown Beige plaid P27 Interior (ED)
http:/[url=http://www.vw-mplate.com/mplate-29638.png]Click to view image
Camper Interior donor:
[/URL]/www.vw-mplate.com/mcode.php?lang=EN&id=721 (M-Code for interior). |
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kreemoweet Samba Member
Joined: March 13, 2008 Posts: 3897 Location: Seattle, WA
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Posted: Fri Aug 28, 2020 5:23 pm Post subject: Re: Odd rear brake behavior |
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NOVA BUS wrote: |
To review, the booster push rod (point) which nests into the brake manifold is NOT adjustable inside the booster itself ... |
Actually, it is, at least sometimes. The ATE booster pushrod tip is pressed in to the pushrod shank. Sometimes there is a shim washer under the tip, and
removing that and replacing the tip will shorten the pushrod length. Adding more shim washers will lengthen the pushrod length. The new ATE
replacement booster I installed not too long ago had a too-long pushrod, and no shims under the tip. I "manufactured" a shorter replacement tip to
solve the problem. It might have been better to put a shim/gasket between the M/C and booster.
And the "throw-you-through-the-windshield" Chinese booster has a screw-in tip with a knurled locknut, so the pushrod length there
seems designed to be adjustable.
The linkage clearance adjustment on the other side of the booster has no relation to inner pushrod length issues. _________________ '67 bug: seized by the authorities
'68 bug: seized by the authorities
'71 kombi: not yet seized by the authorities
Stop dead photo links! Post your photos to The Samba Gallery! |
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NOVA Bus Samba Member
Joined: April 18, 2005 Posts: 517 Location: Herndon, VA
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Posted: Fri Aug 28, 2020 6:30 pm Post subject: Re: Odd rear brake behavior |
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Yes but I'm strictly speaking of the OE (1972+) ATE, which does not have a washer, and for that WW booster, it did have have some adjustability, it still does not compare to original. You must have access to machine shop equipment, that's great, fab your own parts!!👍 _________________ ********************************
1977 Transporter / Weekender
- GE engine, L-Jetronic w/ hyd. lifters
- Brown Beige plaid P27 Interior (ED)
http:/[url=http://www.vw-mplate.com/mplate-29638.png]Click to view image
Camper Interior donor:
[/URL]/www.vw-mplate.com/mcode.php?lang=EN&id=721 (M-Code for interior). |
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