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Vans Brake O Ring SB

Yeah, seems like a great item to bump up the price since everyone will changing them after this letter. Should never be this much. I just bought some from grove and it was 80 cents each.
 
Yeah, seems like a great item to bump up the price since everyone will changing them after this letter. Should never be this much. I just bought some from grove and it was 80 cents each.

I would at least make sure you get mil-spec o-rings. I just redid my brakes, and I used o-rings based on the size "equivalent mil-spec size". As soon as I had everything reassembled, and used the brakes, they were leaking from the top.

For example, Aircraft Spruce shows MS28775-010 (just a random example to show the point) as:
ID: 1/4 (.25)
OD: 3/8 (0.375)
Width: 1/16 (0.0625)

So I got the ole o-ring box out and found those sizes. Leaked.

If you look at the actual mil-spec, MS28775-010 is:
ID: 0.234 - 0.244 (always smaller inside hole)
OD: 0.368 - 0.390 (possibly bigger around, but on average the same)
Width: 0.067 - 0.073 (always taller)

When I got them and lay them side by side to the ones from the o-ring box that are supposedly the same size, you can perceive the differences in them by sight. Separately I don't know that you could ever tell. Haven't had a leak since, and as I assembled my master cylinders, these o-rings were noticeably snugger on assembly, and in operation.

I would make sure you get actual mil-spec o-rings.
 
Yeah, seems like a great item to bump up the price since everyone will changing them after this letter. Should never be this much. I just bought some from grove and it was 80 cents each.

Are they the compound rated to -40F?
 
I'm missing something major here with safety updates. It's not listed on the vans website under any model in the "safety and service documentation" section, and there was no email from Vans about the release even though I'm signed up for the "updates" email list. Short of following the link posted here, I can't find the document on the vans site. I'm surprised the unofficial forums is the best way to get safety updates.
 
I'm missing something major here with safety updates. It's not listed on the vans website under any model in the "safety and service documentation" section, and there was no email from Vans about the release even though I'm signed up for the "updates" email list. Short of following the link posted here, I can't find the document on the vans site. I'm surprised the unofficial forums is the best way to get safety updates.

Maybe there's lag from when they post the doc to when they update the SB list here, but it's the first thing listed under Notifications and Letters for any airplane I chose that it applies to.
 
Am I missing something on this O ring? Vans lists this as $5.50 so seems fairly pricey for an O ring.

https://www.vansaircraft.com/service-information-and-revisions/sl-00047/

https://store.vansaircraft.com/catalogsearch/result/?q=Brake+o+ring

20 + years ago, Randy Lervold (I think it was him or that is who I found out from) discovered that Viton O-Rings were higher temperature rated than the MIL spec O-Ring used in our brakes. The only downside is that Viton would not remain soft to the same cold temperature. Many of us in the Southwest where it was warm year round switched to Viton O-Rings.

20-years ago, I could get the Viton O-Rings for our brakes for about $1 each when I purchased 100 at a time.

Most things aviation have gone up by a factor of 4 over the past 20-years. Van's O-Ring for the brake sounds like it is an improved compound based on Viton because it remains soft to a lower temperature. Price appears to be in in line with other aviation part expenses.
 
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Reading the service letter it refers to “older brake calibres”. We have just received our finishing kit so can we be sure that we have the new seals installed. Just saying older does not really help us. Usually ranges of serial numbers or before dates are specified.
 
Viton is best

I had numerous leaks with Buna O-rings that came with my Matco calipers. I changed to Viton a few years ago and not a leak since. YMMV.
 
Reading the service letter it refers to “older brake calibres”. We have just received our finishing kit so can we be sure that we have the new seals installed. Just saying older does not really help us. Usually ranges of serial numbers or before dates are specified.

The way I read the SB, you have the old O rings. Everyone does. These are an extra-cost option. Also the way I read the SB, these are not generic viton, but a special material that is useable to a lower temperature.
 
Anyone have an AN or MS PN for these new 'O' rings?

I don't think there's an AN or MS PN for these new V1038 'O' rings. There are MIL-R-83248 Viton O-rings, but they have a min temp of zero F.

We know that the size is 218, and Buna-N O-Rings in that size can be had for less than $1.00 each. Ordinary Viton O-Rings are about the same price when bought in quantity.

McMASTER-CARR has low temp Viton O-Rings; two for $12.05, but they are not the same durometer.

These are specialty items. I've found them at an O-Ring supplier, but instead of a price, there was "Please submit a quote request".

I've never known Van's to price gouge on anything.
 
Thanks for the post

Missed this SB and have had the leaking caliper problem in the middle of winter here in Oklahoma, $10 to stop having to pull the wheel pants and brakes apart in a freezing hangar is well worth it.
Figs
 
Cleveland VS Matco

Older kits had Cleveland brakes and the newer kits are Matco. Van's website says that the o-ring fits Cleveland. Nothing is mentioned about Matco. Are the o-rings interchangeable between the two manufacturer's?
 
I-ring / hydraulic fluid compatibility

And some of us, well me at least, received Cleveland wheels/brakes, along with Matco brake cylinders.

Bottom line is, CHECK ALL THE O-RINGS in the system for compatibility with the newer hydraulic fluid. That is unless you’re OK with a leaking brake system some time in the future.

Best source of information on compatibility is, as always, the manufacturer of the component in question.
 
And some of us, well me at least, received Cleveland wheels/brakes, along with Matco brake cylinders.

Bottom line is, CHECK ALL THE O-RINGS in the system for compatibility with the newer hydraulic fluid. That is unless you’re OK with a leaking brake system some time in the future.

Best source of information on compatibility is, as always, the manufacturer of the component in question.

To be more clear I was asking if the o-ring will fit both the Cleveland and Matco caliper / pucks? Or are they for the Cleveland only?
 
I had contacted some manufacturers and distributors in 2019 about sourcing the low-temp Viton O rings, they were just under $3 each but I gave up when the minimum quantity was 148 pieces. Five bucks from Van’s sounds pretty good.

No mention of the material in the SB that I saw, but the stuff I found was Viton GLT or GFLT (VM125 or VM835). I’ve had blue fluorosilicone rings from McMaster in my calipers for the past 10 years, which have worked fine in cold temps. I later read that they have some durability disadvantages though, which sent me down the low temp Viton rabbit hole.
 
Matco is -222 size oring

To be more clear I was asking if the o-ring will fit both the Cleveland and Matco caliper / pucks? Or are they for the Cleveland only?

AFAIK Van's Matco Wheels & Brakes PN U-00010 is Matco PN WHLWE51 which comes with caliper WHLBE5 which uses piston oring Buna N size -222. Matco says to use MIL-H-5606 fluid.

Van's oring PN U-00015-1 is GLT (good for low temperature) Viton size -218 which fits Cleveland 30-9 calipers.

Matco caliper dwg: https://static.veracart.com/matco/item_pdfs/2656/document1.pdf
.
 
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Well now that I've ordered the o-rings from the Service Letter for my Matco brakes it appears that those are the wrong O-rings.

I then went into a rabbit hole searching for the V1038, Viton low temp o-rings. While -15F or -20F Viton is pretty available the low temp version is not. I did put in a quote request at one of the o-ring suppliers and I got a response back with a minimum quantity requirement. So now that I know more about o-rings than I ever wanted to know I'm at the point of either not installing Viton o-rings, installing standard temp Viton o-rings, or ordering the V1038 o-rings. If I could get a few folks that want the low temp Viton o-rings I might be able to make that work. The quote that I have for the low temp -222 o-rings is about $8/ea for those that might be interested.

I guess this is why its called experimental aviation. In the end its another experiment to be made.
 
Well now that I've ordered the o-rings from the Service Letter for my Matco brakes it appears that those are the wrong O-rings.

I then went into a rabbit hole searching for the V1038, Viton low temp o-rings. While -15F or -20F Viton is pretty available the low temp version is not. I did put in a quote request at one of the o-ring suppliers and I got a response back with a minimum quantity requirement. So now that I know more about o-rings than I ever wanted to know I'm at the point of either not installing Viton o-rings, installing standard temp Viton o-rings, or ordering the V1038 o-rings. If I could get a few folks that want the low temp Viton o-rings I might be able to make that work. The quote that I have for the low temp -222 o-rings is about $8/ea for those that might be interested.

I guess this is why its called experimental aviation. In the end its another experiment to be made.

I don't see me needing the colder temp o-ring so I went with the AS568-222's (I have Matco) from the O-ring store. Min. $5 order so ordered 5 of them at $1.04/each and I'm not required to order 95 more necessary o-rings. Shipping is still double the cost of the o-rings. We'll see how these work.

https://www.theoringstore.com/store/index.php?main_page=advanced_search_result&search_in_description=1&keyword=V75222-MS
 
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I received my o-rings from the O-Ring Store so today I'm planning on doing the o-ring swap today and I'll try to get off of this side track that I somehow took. It looks easy enough. I did a test to blow out the brake cylinder and that worked as expected. Thanks for those who provided guidance.

I did end up with a set of Viton o-rings from Vans which are unusable for me so if anyone was thinking of swapping their Cleaveland o-rings I have a set available.
 
And some of us, well me at least, received Cleveland wheels/brakes, along with Matco brake cylinders.

Bottom line is, CHECK ALL THE O-RINGS in the system for compatibility with the newer hydraulic fluid. That is unless you’re OK with a leaking brake system some time in the future.

Best source of information on compatibility is, as always, the manufacturer of the component in question.

No need to worry about the compatibility. The Mil-PRF-83282 hydraulic fluid is compatible with all materials that the standard Mil-H-5606 hydraulic fluid is. The reason to switch to the Viton O-rings is to gain the high temperature capability to match the capability of the hydraulic fluid.

By the way, Royco 782 hydraulic fluid (available at ACS) is Mil-PRF-83282.
 
Brake SB

So if you get the O rings from Vans to put in the calipers (Cleveland) and swap the hydraulic fluid do you have to rebuild the Matco brake master cylinders to swap out those O rings? Do the brake master cylinder rebuild kits on Vans & Acft Spruce have compatible O rings with the new hydraulic fluid?

Sounds like the fluids are OK to be mixed but just not sure about the master cylinders since there isn’t info in the SB about doing anything to them as well.
 
So if you get the O rings from Vans to put in the calipers (Cleveland) and swap the hydraulic fluid do you have to rebuild the Matco brake master cylinders to swap out those O rings? Do the brake master cylinder rebuild kits on Vans & Acft Spruce have compatible O rings with the new hydraulic fluid?

Sounds like the fluids are OK to be mixed but just not sure about the master cylinders since there isn’t info in the SB about doing anything to them as well.

The current seals work with the newer high temperature fluid others have mentioned. I swapped to the Mil-PRF-83282 fluid about 20-years ago after seeing a friends RV-8 have a wheel pant destroyed from a 5606 brake fluid fire. I did not change any of the seals at that time.

I recommend changing the brake caliper O-Ring to the new high temperature one Van's sells or to a Viton O-Ring just because the newer materials withstand more heat. Viton may have the same high temperature rating as the one recommended by Van's but Viton will not be as flexible at very low temperatures. The heat is confined to the caliper and is not necessary to have high temperature o-ring seals in the master cylinders. The master cylinders are in the cool cockpit with the pilot not down with the heat generating friction brake material.

The Cleveland and Matco seals do need replaced from time to time. I went to Viton only in the brake caliper years ago. I still use the Mil Spec O-Rings in my Cleveland master cylinders. It is a lot less money to buy the mil spec o-ring listed on the Cleveland parts list than the Cleveland rebuild kit. Matco master cylinders has one seal that I have not been able to find. The $15 to $18 dollars that the Matco rebuild kit from Aircraft Spruce has everything and is worth the few dollars extra to have everything including that one seal that I have never been able to find any other way. The one I am talking about is like a washer with an o-ring on the inside hole.

Hope this helps.
 
For those of you like me who have never disassembled a Matco caliper and were wondering what it looks like on the inside there really isn't much to it. The cylinder is very basic too with a small bump on the back that acts as a spacer.

In regard to my excess Cleaveland Viton o-rings how about a small donation to Doug and I'll cover the postage. I have 3 o-rings available since I bought enough to have a spare after the swap.
 

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For those of you like me who have never disassembled a Matco caliper and were wondering what it looks like on the inside there really isn't much to it. The cylinder is very basic too with a small bump on the back that acts as a spacer.

In regard to my excess Cleaveland Viton o-rings how about a small donation to Doug and I'll cover the postage. I have 3 o-rings available since I bought enough to have a spare after the swap.

As an engineer I have always cursed designers that put the o-ring gland on the cylinder bore rather than on the piston. It makes it much harder to service. But in this case there is a benefit. I have found several examples of people who have put the piston puck in backwards, with the o-ring gland too close to the face that contacts the brake pad rather than with the o-ring on the face that is deepest into the caliper housing. The result is that it is possible to wear the brake pads enough that the o-ring will come out of the cylinder bore and leak, and of course this happens while braking, so serious chance of a fire. So in this case, putting the o-ring gland in the cylinder bore prevents this mistake. Of course, so does properly assembling the parts....just sayin'
 
Easier

As an engineer I have always cursed designers that put the o-ring gland on the cylinder bore rather than on the piston. It makes it much harder to service. But in this case there is a benefit. I have found several examples of people who have put the piston puck in backwards, with the o-ring gland too close to the face that contacts the brake pad rather than with the o-ring on the face that is deepest into the caliper housing. The result is that it is possible to wear the brake pads enough that the o-ring will come out of the cylinder bore and leak, and of course this happens while braking, so serious chance of a fire. So in this case, putting the o-ring gland in the cylinder bore prevents this mistake. Of course, so does properly assembling the parts....just sayin'

Much easier to machine a groove in a piston than one in the cylinder. Just saying. I am glad they didnt take the easy way out, like you mentioned.
 
The benefit I see with the O ring in the cylinder is the piston and the cylinder has less area exposed to the elements. And only the piston gets exposed with pad wear.
 
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