REAR disc "CALIPER setup HOW-TO" (e-brake/parking brake)

[Sodo]

====== EDIT =========
These instructions are for the Girling 4143 caliper, as sold by Smallcar.com and Burley from appx 2009 to 2016.
For the PROCEDURE, jump to page 2. Its simple.
My rear discs had no parking brake for 7 years. Now it will hold the van on a hill, but just barely. Also doing an emergency stop, braking power was undetectable. Now it holds back a little, stopping the van from 20mph in 72 feet. Not great for emergencies.

Others claim their brakes work better than this. I would prefer better performance, but I'm enjoying at least SOME parking brake now.

===================

Some folks are claiming their Audi parking brakes work and for that I am extremely envious. Mine have ZERO (to 1%) parking brake therefore it must be a "setup problem". If there exists a method, I'm hoping to create a HOW-TO thread with a specific, searchable subject. Here goes.

My rear brakes were installed by Smallcar in 2009. I took it back and mentioned the parking brake didn't work. They clickety-clicked it, felt the pull on the handle and proclaimed "I tried it, it feels fine". They did not address "holding power" didn't even move the van, just pulled the handle.

The behavior of my brakes suggests that the ebrake mechanism is NOT producing any squeeze upon the pads. While the Hydraulic footbrake performance is "stellar", the handbrake is about a ZERO ....

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So far, I've found two different Audi brake setup schemes that contradict mightily. Does anyone have a procedure from Burley?

Samba member wesitarz recently posted the UK info. Reading thru the UK Audifans site caliper disassembly instructions page the UK audi fella (Phil Payne) instructs (in a much more detailed manner):

1) Preset the initial position of the caliper piston carefully (by screwing piston outward on its e-brake screw). On the piston preset page he tells you to measure the stackup of the pads/disc you have and preset the piston on its e-brake screw with 1mm clearance (for fitting).
2) bleed the brakes completely using the footbrake. Be careful to NOT MOVE the ebrake actuator before the hydraulic system is completely bled. he recommends to disconnect the handbrake cable, to ENSURE the caliper e-brake actuator is not moved prior to bleeding the hydraulics.
THEN
3) the handbrake being preset will self-adjust with use.

Contrast this with Smallcar instructions (unchanged since ~2009):

Smallcar disc brake instructions:

1) operate the handbrake cable 20-30 times
THEN
2)bleed the brake fluid.

So here we go. I got calipers off, gotta do something else for awhile but back at it this eve or tomorrow. Anybody want to work along?

Does anybody on theSamba have experience setting up these brakes?
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'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[wesitarz]

Have you backed off the adjusting nut at the equalizer bar under the van? This would be your final adjustment as your cables are probably pulled really tight now? I suspended the equalizer bar loosely from the frame so it would pull more equally on each brake cable. Hope it works for you.

[Sodo]

I loosened the nut at the equalizer bar all the way then disconnected the cables, and removed the calipers. The plan is to setup the calipers per the UK Audi guy's instructions and put it back together.

How is everyone else doing it?

Handbrake first then bleed. (Smallcar method)
or
Bleed first, then handbrake (UK Audi method)

_________________


'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[Michael4104]

[Rjhdog]

[Sodo]

Micheal certainly returning to drums is an option if this plea goes dark like others have. I spent $1100 on this kit and have been trying to resolve this since 2009. I should have asked for them to switch it back. I don't have my parts anymore but would LIKE to make these discs work at least as well as some other members have.

Discs (especially vented discs) are better than drums for stopping power. Especially on long downhills, higher speeds, and the heavier GVW that of bigger engines have offered our old vans. You can carry more stuff, and stop. They handle overheating better. There are some good reasons. People do get kinda frustrated with drum brakes though, I don't know if its genuine or just the spectre of shiny new discs is what sours them to re-newing their drums.

But the parking brake (or the safety of a last-ditch-effort emergency brake) are not as good as a drum, in comparison. Mostly because a drum brake is self-energizing, which means when you try to rotate the drum, it draws the brake shoe in 'tighter'. This works even better 'from stopped' or parked, resulting in higher static friction, resistance to 'get rolling'. Discs cannot do this, once they slip a little, they require INCREASED pressure, which a foot or brake-booster can do, but an un-manned cable cannot. Thus the Van rolls.

I started this thread IN HOPES we can get theSamba minds together to "publish" a method on the forum, HOW to get a disc-parking brake to work. Some members out there have WORKING disc parking brakes. How did you do the initial setup of the caliper? I composed this subject title carefully to be searchable to Samba members with rear disc "upgrades". I respectfully ask to keep this discussion to Rear Disc parking brake setup.
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'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[Zeitgeist 13]

What is this, like your sixth thread on this very topic? Have you looked at Audi and/or EV brake setups with the exact same parking brakes? I have both vehicles in my driveway, and they each work perfectly fine. I've never once had to adjust the parking brake on my Audi, even though I've owned it for over a decade.
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[Christopher Schimke]

So...in light of all that you have tired over the years and seeing how you generally take the scientific/engineering approach to things, why not go into this as a two-part experiment.

A few people have claimed to have changed nothing but the cables which resulted in better parking brake performance. I know you have shunned that idea in the past, so why not try the "UK way" to adjust the calipers and if that doesn't work, try a set of the Lokar universal cable kits just to put that to rest one way or the other.

If you try those last two things, I can't think of any other thing that you could possibly try other than moving on to something else. At least that way you can say that you have literally tried about every single thing possible to get them to work.

Just a thought!
_________________
"Sometimes you have to build a box to think outside of." - Bruce (not Springsteen)

*Custom wheel hardware for Audi/VW, Porsche and Mercedes wheels - Urethane Suspension Bushings*
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[ragnarhairybreeks]

I appreciate what you are doing Sodo. I don't see it as beating a dead horse, I see it more of separating the wheat from the chaff.

Stop me before I use any more metaphors.

I hope this thread stays on track, a technical exploration, and that my show of support does not lead to an off topic derailment.

Keep it up Sodo,

Alistair
_________________
'86 7 passenger syncro, converted to westy pop top, project still in progress
'82 westy, diesel converted to gas in '94, now gone...
https://shufti.blog/
Old address still works...
http://shufti.wordpress.com

[crazyvwvanman]

Looking at the Audi Bentley for the 5000 family up through 1988 it shows a couple variations of the rear calipers with some differences in setup procedures. They emphasize the need to leave the parking cable adjustment for last and do the basic setup first while making sure the cables are loose.

What markings are on the calipers in question? Brand, numbers....

Mark

[Sodo]

[hans j]

No real setup for me. I just made sure the park brake cables had the correct tension on it like a factory VW rear caliper. Then I just adjusted the center nut until the cables weren't too tight, and weren't too loose. No adjustments have been needed since then, almost 55000 KM ago (over 34000 miles).
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1986 Canadian Syncro Westy TDI - 1989 Syncro Single Cab - 2001 Audi S4 - 1981 VW Caddy ABA - 1980 VW Caddy EV - 1973 VW T-181

[wesitarz]

My kit was installed by a shop .I gave them the Smallcar instructions and they didn't say they had a problem or changed anything,so I don't know what they did for sure. I did change the pads last year to PBR ceramics and screwed the piston in using my big C-clamp which actually turned the piston (next time I'll use the proper tool) and wasn't too particular about the clearance - just enough to get the caliper back on. I did pump the pedal and bleed before pulling the handbrake lever for sure and everything worked OK. I have not re-adjusted at the equalizer bar under the van.

[mtnhome]

[Pcforno]

Sodo- have you tried activating the ebrake caliper mechanism by hand with the brakes off the car? Perhaps you could rig up something with some leverage to pull on the caliper actuator whilst in a vice or something. Maybe the mechanism is stuck?

[Sodo]

These calipers have 30,000 miles. I don't know if they were new when installed at Smallcar, that one looks pretty old.

PC thats a great suggestion, too dang simple I tellya. It should advance the piston of course!! I've never tried it without a disc.

Can see (passenger side) tightening the pads onto the disc. But theres no way to guess how hard its gripping until driving it. Will try it with no disc to see if it appears to advance beyond the disc thickness.

All the sliders look good, will add grease and reassemble, try to set it up like UK guys instructions, (and bentley) do all the bleeding etc first.
_________________


'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[Howesight]

Mrs. Howesight and I both drive modified URS4/6 Audi cars. Although the front brakes are modified, the rear brakes we use are stock, in excellent condition and properly adjusted. They are the same set used in the SmallCar kit and a few other vendors' kits.

I have to say, they are quite weak on the parking brake application which I know because I like to do e-brake turns whenever Mrs. Howesight becomes complacent with my more hum-drum driving. I find I can only do a good e-brake 180 (or 270) turn on shiny concrete and barely any e-brake turn on asphalt.

I realize that the requirements on the Syncro Westfalia have more to do with not rolling off the campsite into the river than the ability to do any hooning. Absent you folks finding a solution, I would not use these brakes to hold my Westy overnight. On my Westy, I still have my antique drums which I admit are not great for dissipating heat.

Sodo, if you and other posters here solve this mystery, I am ready to try some of my Lucas caliper spares on my Westy. Apart from the Lucas rebuild data sheet and my comments above, I can't contribute much to this discussion.

Here's a link to the exploded view of this brake system with part numbers:

http://12v.org/urs/RearBrakePNs.jpg

Here's a link to the Lucas publication XZB137on these Lucas Calipers:

http://www.20v.org/brakere.htm
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'86 Syncro Westy SVX

[WLD*WSTY]

[Sodo]

Thanks Howesight for your assessment of URS4/6 brakes. I don't know anything about a URS4/6, but you wrote that your car(s) having Lucas calipers. The Smallcar and others use Girling 4143 calipers. Knowing Audis (or at least the URS4/6 model) do you think these piston preset instructions apply to the Girling 4143 calipers?

The "UR-quattro" instructions unearthed by Wesitarz include the words "5-cylinder Mechanic", FWIW.
Mark referred to Audi 5000 procedures. WildWsty, I have not proceeded on these "UR-Quattro" instructions yet, have been procrastinating on other projects, hoping more "setup info" will float up on theSamba. I need to first look inside at the e-brake mechanisms prior to bolting them back on, so have a little time.

The plot is thickening. I need help with the language of Lucas, Girling4143, URS4/6, Audi5000, 20v and UR-quattro etc. Can anyone translate this to Girling 4143?

Phil Payne (UK guy) writes in his UR-Quattro instructions in step 2&3 of setup conditions: "if there is play between the piston and pads, handbrake function will not be achieved." Note he previously recommended cables be disconnected to avoid even wiggling the actuator lever during initial setup.

Wesitarz that's interesting yours were installed with no fanfare. If any of you Girling4143 (smallcar/burley) owners have trick you have used (unknowingly?) please reply.
_________________


'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[wesitarz]

The caliper and pads are from a 90-94 Audi V8 quattro. The rotor is from a 91 Audi 200 quattro 20v (Zimmerman). I don't see an external handbrake adjustment screw on these calipers so they must be self-adjusting like the ur quattro. Both are the same vintage (80s and 90s) so I think the mechanism should be similar if not the same. The other thing to consider is that the kits contained reman calipers. Does reman include a new handbrake mechanism - probably not in my mind. Maybe some are more worn than others. You can check them out on Rockauto. On some pics you can see 4143 last time I looked.
How did my pad replacement work? Just lucky I think. I want to replace the flex lines with SS and replace the rotors with new Zimmermans next spring,so I will have them apart again and plan to do it the UK way with the right piston tool. Looking forward to your outcome and write-up.