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Sodo
Samba Member
Joined: July 06, 2007
Posts: 9610
Location: Western WA
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 Posted: Tue Jan 26, 2016 10:16 am Post subject: Parking brake test (disc and drum) |
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Can your parking brake hold the van parked, in neutral, partway up a standard wheel ramp? Van on level ground.
Don't get carried away with details, just trying to get some basic data with regards to parking brakes to compare "disc brake upgrades".
Data point #1: My rear disc brake (SmallCar 2009) cannot hold the van on the ramp, I have to put it in gear or it just rolls down. My wheels are 27.7", appx 10% bigger than stock.
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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
Last edited by Sodo on Fri Jan 29, 2016 3:39 pm; edited 5 times in total |
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dobryan
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Joined: March 24, 2006
Posts: 16504
Location: Brookeville, MD
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Sodo
Samba Member
Joined: July 06, 2007
Posts: 9610
Location: Western WA
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| Posted: Tue Jan 26, 2016 10:21 am Post subject: Re: Parking brake test (disc and drum) |
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'Standard' ramps may be more reliable than members grade measurements, or estimates, or comprehension.
Probably better to keep it simple.
_________________
'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 |
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dobryan
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Location: Brookeville, MD
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ZsZ
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Joined: December 11, 2010
Posts: 1647
Location: Budapest Hungary, Europe
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| Posted: Tue Jan 26, 2016 12:35 pm Post subject: Re: Parking brake test (disc and drum) |
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When the pads and the drums were new it held the van in any position. Since that I had bad wheel cylinders and the shoes were contaminated with brake fluid. Couldn't wash all the fluids out and not had the budget to throw away the almost new shoes. Now it is not perfect but works. It allows about a half of a meter slip.
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Zoltan
1.9 MTdi 2wd Multivan (ex Caravelle)
Van since 2006, engine since 2008 |
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dobryan
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Location: Brookeville, MD
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Sodo
Samba Member
Joined: July 06, 2007
Posts: 9610
Location: Western WA
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| Posted: Tue Jan 26, 2016 6:49 pm Post subject: Re: Parking brake test (disc and drum) |
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Not sure, the van's not parked like that anymore. Looks to be half a wheel radius, 6 3/4 inches.
_________________
'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 |
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dobryan
Samba Member
Joined: March 24, 2006
Posts: 16504
Location: Brookeville, MD
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| Posted: Tue Jan 26, 2016 9:03 pm Post subject: Re: Parking brake test (disc and drum) |
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| Sodo wrote: |
| Not sure, the van's not parked like that anymore. Looks to be half a wheel radius, 6 3/4 inches. |
OK go out and redo the test and measure it. If you want us to give you repeatable results you need to give us a real test baseline. Do the test to the point where your parking brake will not hold and tell us what the height is and then ask at what height our rear disc brake conversions will hold.
You said you want real data, give us real data to comare to.
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Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD
"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson
MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646
Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371
The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794 |
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Sodo
Samba Member
Joined: July 06, 2007
Posts: 9610
Location: Western WA
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| Posted: Tue Jan 26, 2016 9:46 pm Post subject: Re: Parking brake test (disc and drum) |
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What's your reasoning that the height makes a difference? You're thinking that as it comes down the ramp it takes less to hold the van there? I doubt it, but cant prove it because my brake can't hold that slope at all.
Its the slope, period and as long as the wheel is on the slope there is no difference in the braking power required to hold it there. A measurement that would provide more accurate comparison is the slope.
Also I'm pretty sure its gotta be simple " = the ramps ya got" or nobody's gonna do it.
EDIT: OK just put on my fuzzy slippers and measured my ramps. My ramp has a constant slope 1/2 = 8" rise in 16" run.
_________________
'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
Last edited by Sodo on Tue Jan 26, 2016 10:21 pm; edited 6 times in total |
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dobryan
Samba Member
Joined: March 24, 2006
Posts: 16504
Location: Brookeville, MD
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| Posted: Tue Jan 26, 2016 9:58 pm Post subject: Re: Parking brake test (disc and drum) |
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If you want a repeatable test you need to give repeatable dimensions.....
Just saying that my 'ramp' doesn't hold my parking brake is not good
enough. If you can not get scientific about this then what is the point? I'm trying to help but I'm not getting much help here. You do understand that the slope is what creates the force that the parking brake is trying to counteract? That lift dimension is critical. Give me REAL data to compare to or I am out of here.
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Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD
"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson
MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646
Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371
The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794 |
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IdahoDoug
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Joined: June 12, 2010
Posts: 10250
Location: N. Idaho
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| Posted: Tue Jan 26, 2016 10:30 pm Post subject: Re: Parking brake test (disc and drum) |
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That ramp comparison is actually going to be a difficult thing. The minor difference in slopes of various brands makes an enormous difference in force required to keep it from moving. In addition, we all typically back down a hill in our drives and up onto ramps, so thats another pretty big variable - how sloped is your drive.
However, it may be the best we've got.... I predict the drum brake crowd will have way better average holding power. A parking brake cable and lever designed for a drum brake is simply not going to generate as high a level of holding power when it is instead activating a caliper/disc.
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader |
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Sodo
Samba Member
Joined: July 06, 2007
Posts: 9610
Location: Western WA
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| Posted: Tue Jan 26, 2016 10:48 pm Post subject: Re: Parking brake test (disc and drum) |
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| IdahoDoug wrote: |
| That ramp comparison is actually going to be a difficult thing. |
I dont think so. Getting down to the nitty-gritty is difficult.
Post #1 describes a simple test, and I think it can give good results. And there's a pic. Prob doesn't require further complication. Does your parking brake hold on a ramp or not?
If there was more than one data point maybe we can discuss grounds to change the test. But I just edited to add "level ground". Other than that I still think its a good test. After a few more data points, further refinements can be peoposed to get better data. Fair enough?
_________________
'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 |
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dobryan
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Sodo
Samba Member
Joined: July 06, 2007
Posts: 9610
Location: Western WA
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| Posted: Tue Jan 26, 2016 10:56 pm Post subject: Re: Parking brake test (disc and drum) |
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8" rise in 16" run
_________________
'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 |
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dobryan
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Sodo
Samba Member
Joined: July 06, 2007
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Location: Western WA
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| Posted: Tue Jan 26, 2016 11:26 pm Post subject: Re: Parking brake test (disc and drum) |
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I ran it up, and it slipped down, several times. I don't know what sense it makes to pick a height (for mine) because my brake "fails" From the top all the way to the bottom. I had to put it in gear to hold it on the slope so I could provide a pic of my example test. I apologize I'm not comprehending what you're after.
If your brake happens to hold on a similar slope there may be conclusions that you can make. You can say "well, it holds, but barely". Or "I would circumcise my son in front of that wheel!"
But for mine, the only way to make conclusions is to vary the slope. That's a different test. I think its better to start with a simple one where you just get out your ramps, post a data point. This one is more digital. (Hold or not)
Dave I do understand is why you need the dimensions of my ramps. 
_________________
'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 |
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61Scout
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Posts: 1297
Location: Shoreline/Yakima WA
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| Posted: Wed Jan 27, 2016 12:06 am Post subject: Re: Parking brake test (disc and drum) |
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Hey all, just wanted to make a quick PSA about ramps since it's winter. IF you have plastic ramps, be sure to read the temperature rating for them. Although the plastic ramps are typically rated for a higher load (you'd think it would be the other way, but it's not) than steel they have two negatives. UV breakdown, which all plastic suffers from to some degree... but point being don't leave your ramps out baking in the sunlight. And the second weakness is that plastic ramps can't be used in freezing temperatures. So just a heads up for anyone working on ramps. Be safe.
-Kevin
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1986 Westfalia Weekender Wolfsburg, RJE 2.3
1985 Tin Top, Subie 2.2 + 5MT
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Wellington
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Joined: September 21, 2004
Posts: 1889
Location: Montreal
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| Posted: Wed Jan 27, 2016 3:49 am Post subject: Re: Parking brake test (disc and drum) |
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| I think tire size may come ito play. |
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Tom Powell
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Posts: 4855
Location: Kaneohe
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| Posted: Wed Jan 27, 2016 5:39 am Post subject: Re: Parking brake test (disc and drum) |
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Test your parking brake on Eldred Street
Aloha
tp |
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svenakela
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Location: Ekerö
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| Posted: Wed Jan 27, 2016 6:29 am Post subject: Re: Parking brake test (disc and drum) |
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No problem with parking brake here.
My experience is that most of the p-brake problems are related to non-VW calipers. It tried new copies once but replaced them with used VW-calipers after a week and no problems since.
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