Brake wizard needed in Costa Rica. Maybe I'll pay your way

Issues with shocks/springs, tires, stopping, etc.
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junglefever
Costa Rica
Posts: 9
Joined: Wed Dec 10, 2008 10:48 am

Brake wizard needed in Costa Rica. Maybe I'll pay your way

Post by junglefever » Sat Mar 27, 2021 8:28 pm

Someone please help with this brake dilemma. My Pinz is located in Costa Rica and every year I need to pass a safety inspection the likes of nothing I have ever had to deal with anywhere else...( Russia, Africa, USA).. None of them come close.. Anyway. I just failed another 6 times in three days trying to get the brakes to pass. Its all computer analyzed up on rollers and the fronts will grab like no bodies business but I cannot get anything to the rears. Always happens that way. I made some metal hoops of 1 inch wide steel to wrap around rear shoes to keep wheel cyliders from blowing the seals out while I had someone working the brake pedal just so I could see what was going on. Rears do not even think of moving with a slow steady push off the pedal like they demand at the inspection. If my helper stabs the pedal hard and fast there is some movement the rears but not impressive by any means. Won't even come close to the specs needed to pass. I have tried everything over the years. All new wheel cylinders, new lines and hoses, new master, new shoes.. machined drums incase they were warped, bled the system so many times I cant count. Tried backing way off on adjustments of fronts to allow more pedal travel hoping it will help the rears (Nope!)....Even adjusted rears so tight they would have been smoking if I drove more then the 200 meters to get it back to the inspection place.. I am at a loss and ready to treat someone to a full on Costa Rica adventure holiday if you have some ideas that might work. I am dead serious. This inspection nightmare costs me loads of dough every year, undue stress etc....and once you fail, you are a marked man. The cops nab you driving after the fail and there goes your Pinz off to the impound and sell your soul to get it back. It's a three hour drive just to get to the damned place so I am sticking my red neck out there......I am open to any and all suggestions. Is there a proportioning valve I am unaware of?

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pcolette
United States of America
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Location: Southwest Wisconsin

Re: Brake wizard needed in Costa Rica. Maybe I'll pay your way

Post by pcolette » Sat Mar 27, 2021 11:10 pm

On one of the 710M's I bought years back, I had a similar problem with lack of braking in one circuit. It turned out that one of the Static Pressure Valves, part # 7103366220, had been installed backwards preventing the flow of brake fluid.

The attached photo has the 2 valves marked with arrows. Worth a look anyway.
IMG_2025.jpeg
IMG_2025.jpeg (393.03 KiB) Viewed 557 times
Paul C.
_________
'73 Swiss 710M
'89 Puch 230GE
2002 MB G500

junglefever
Costa Rica
Posts: 9
Joined: Wed Dec 10, 2008 10:48 am

Re: Brake wizard needed in Costa Rica. Maybe I'll pay your way

Post by junglefever » Sun Mar 28, 2021 11:59 am

Thanks a lot for the tip. I am hitting the trail to hike out of the jungle now to get a look and see what is up in there on that master. Man that would be so great if that is the issue. I do get some action to the rears if the pedal is pumped up so maybe that valve is an issue.. Or non existent. Thanks for the tip..

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Hotzenplotz
Austria
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Location: Vienna, Austria

Re: Brake wizard needed in Costa Rica. Maybe I'll pay your way

Post by Hotzenplotz » Sun Mar 28, 2021 12:25 pm

Just out of curiosity: did you
  • adjust the rear brakes ?
  • bleed the rear brakes ?
  • if you bled them, was the fluid trickling or spraying ?
I assume your Pinz is of Swiss Origin; they have one circuit for the front and one for the rear.
You could also have an issue with the master cylinder leaking between front and rear. The left (outside) pipe supplies the front axle and the one closer to the servo the rear axle. There is a floating piston between these spaces in the master cylinder. If that piston leaks you have the symptoms you describe.
Cheers
Albert
========================
My Pinz has NEVER been with any army

lifefloat
United States of America
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Location: Florida Keys

Re: Brake wizard needed in Costa Rica. Maybe I'll pay your way

Post by lifefloat » Sun Mar 28, 2021 2:39 pm

[quote=Hotzenplotz

I assume your Pinz is of Swiss Origin; they have one circuit for the front and one for the rear.

[/quote]

Out of curiosity, is the Austrian brake circuit different?

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Hotzenplotz
Austria
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Joined: Wed Jan 18, 2012 9:07 am
Location: Vienna, Austria

Re: Brake wizard needed in Costa Rica. Maybe I'll pay your way

Post by Hotzenplotz » Sun Mar 28, 2021 4:31 pm

yep, it is ...

There are two single brake cylinders on each front wheel and a single tandem cylinder on a rear wheel, in both versions

the Swiss setup has both single cylinders of both front wheels on a connection of the master cylinder, and both tandem cylinders of the rear axle on the other one.
the Austrian setup requires more piping, but creates logical triangles,
there the cylinders of each front wheel are allocated to different circuits, and a rear wheel tandem cylinder is added to the group.

As a result the Swiss model fails either front or rear axle with a failed circuit. the Austrian setup fails half of the braking power at the front axle and one rear wheel

Image
Cheers
Albert
========================
My Pinz has NEVER been with any army

junglefever
Costa Rica
Posts: 9
Joined: Wed Dec 10, 2008 10:48 am

Re: Brake wizard needed in Costa Rica. Maybe I'll pay your way

Post by junglefever » Tue Mar 30, 2021 6:26 pm

Hi...Thanks folksnfor taking the time to help out...The schematic you show of the brakes is not my rig. I have one steel tube that feeds one of the front wheel cylinders and then a short steel tube that leaves that cylinder and goes to the second wheel cylinder of the same wheel. Brakes have been adjusted and bled many times. Master has been replaced in hopes of solving this issue, but it did not... so not likely the master.. Though I guess it could be bad off the shelf. But a real long shot that it would present with the same symptoms. Tempted to see how easy it would be to swap the lines at the master just to see if the problem shifts from back to front.

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Hotzenplotz
Austria
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Location: Vienna, Austria

Re: Brake wizard needed in Costa Rica. Maybe I'll pay your way

Post by Hotzenplotz » Tue Mar 30, 2021 10:13 pm

so your layout is this

Image
junglefever wrote:
Tue Mar 30, 2021 6:26 pm
..... Brakes have been adjusted and bled many times. ...
when bleeding did you see the brake fluid coming with the same pressure at both axles ?

you mentioned at the begin that you had the drums machined. New drums have a diameter of 285 mm. they nay be machined to 287, but the shoes have to be machined, too.
try swapping shoes and drums from front to rear ....
Cheers
Albert
========================
My Pinz has NEVER been with any army

junglefever
Costa Rica
Posts: 9
Joined: Wed Dec 10, 2008 10:48 am

Re: Brake wizard needed in Costa Rica. Maybe I'll pay your way

Post by junglefever » Wed Mar 31, 2021 1:26 pm

Yes, this is my system. I had the same issues before the drums were machined (but that seemed to squeak me past the inspection last year) so I guess it added just enough friction to make the computer happy. I knew it would change the geometry when machining, but decided to take a chance as a last ditch effort in a place where I have limited tools. I would kill to have my whole shop airlifted to Costa Rica.

As for your questions. Well, I never get a real nice strong stream when bleeding the backs.. Nothing like the fronts anyway. That always led me to think the master was weak or the fronts were so close that the pedal stalled out too fast not allowing for rears to get full pressure. But after changing out the master and then backing way off on the front shoes and still having less than ideal pressure when bleeding the rears it kind of stumped me. That is when I decided to change all the rubber lines just incase one had internal collapsing issues going on. I begged the guy machine the drums to just skim them to get rid of any runout and he did just that. I did not have a mic to check the dia real accurately but now that I have those specs (thanks for that) I will sort out a way to check them for dia now. Do you know what the specs should be on the thickness of the lining when new? I have a full set of old shoes down here and was considering getting them relined. That I know I can have done here. Would save me hauling all new sets down on a plane. I cringe at the thought of hauling down 4 new drums. Yikes! Is there any other drum that will fit that maybe I can get here? When I mention Pinzgauer at any shop down here they all tilt their heads and laugh..To be expected. This 710 Is perfect for my needs here so I will fight tooth and nail annually to get it to pass inspection. Thanks again for all the help ..

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Hotzenplotz
Austria
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Location: Vienna, Austria

Re: Brake wizard needed in Costa Rica. Maybe I'll pay your way

Post by Hotzenplotz » Wed Mar 31, 2021 3:52 pm

junglefever

the standard lining for the shoes is 6mm part # 7101364931-1, for machined drums there is a 7 mm version with # 7101364936

additional questions:
  • did you replace the rubber hose in front of the generator fan ?
  • did you check the pressure at the three way connector next to the rear axle ?
Cheers
Albert
========================
My Pinz has NEVER been with any army

User avatar
Hotzenplotz
Austria
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Joined: Wed Jan 18, 2012 9:07 am
Location: Vienna, Austria

Re: Brake wizard needed in Costa Rica. Maybe I'll pay your way

Post by Hotzenplotz » Tue Apr 13, 2021 7:31 am

this thread has fallen asleep. It is safe to assume the issue is fixed.
would you mind sharing details ?
Cheers
Albert
========================
My Pinz has NEVER been with any army

junglefever
Costa Rica
Posts: 9
Joined: Wed Dec 10, 2008 10:48 am

Re: Brake wizard needed in Costa Rica. Maybe I'll pay your way

Post by junglefever » Tue Apr 13, 2021 9:27 am

Hello....I am waking up the sleeping thread... Sorry for the silence. I am in the jungle in Costa Rica doing wildlife research and have limited access to internet connection. I failed at the inspection place so many times dealing with the brakes that I had to give up for now and only drive late at night to avoid the roving police stops looking for the likes of me. This issue has been very frustrating to say the least. On one of the attempts at inspection I backed off the front shoes and cranked down on the rears trying to get more braking power to the rears but it still failed. I tried bringing all shoes up till they were slightly dragging and failed again. Rears always weak and uneven side to side. The Pinz is our up on rollers and a computer analyzes the braking of each wheel and compares them. All have to be within 7% I think. Clearly I failed miserably. The only other suggestion from helpful folks on the forum was perhaps a valve in the brake line near the master is bad. I am considering swapping the front one for the rear one just to see what happens. Sadly I cannot get parts down here unless I carry them myself so that may have to wait until October when I return. Sure would like to solve this issue.

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