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O rings for Scott 4200 parking brake valve


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9 hours ago, carusoam said:

Definitely use caution with steal tools and smooth aluminum sealing surfaces... the hardness differences between the tool and the aluminum can leave a leaky scratch...

Best regards,

-a-

Next time I’ll get my wooden tools I got from Geaorge Washington....

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On 1/23/2019 at 8:55 PM, Marauder said:

 

The 4500 kit won’t work for you. Those O rings are much bigger. Aircraft Spruce has the ones you need. I circled the ones you need. Disregard the B in the number.

 

The new guy at Lasar told me the same thing about my brake master cylinder kit and it was the wrong one.

 

Same thing happened to me from Lasar and flap pump rebuild kit.  I will from now on use the parts manual and order exactly the things needed.  I had to combine two rebuild kits (flap pump and brake cylinder) to just get my flap pump back together with only the essential o-rings replaced.  I will end up doing it again as I know I did not replace all that is needed.

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19 hours ago, PilotCoyote said:

I talked to Univair this morning- their U-4500A1 parking brake is an exact reproduction of the Scott 4500.

they do not sell the valve head or conical seal separately, but the entire valve stem/head assembly is available for $113.15. 2-3 weeks to get it.

part # U4504A  valve stem assembly

Not a bad price considering...

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I just took this picture of the back side of my parking brake valve and (although it’s blurry), now I’m wondering if I have a Scott 4500? Or Mfg. XYZ 4500?

Every picture of a Scott 4500 I have seen look like they were machined from aluminum flat stock. Mine obviously started from a casting.

FDB127AF-B831-4888-803E-C7703BF75A89.jpeg

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  • 2 years later...

Hi supercop0184:

A little late now - but I found these pages from a '58 Scott parts manual for your 4200 series park brake valve. I have (2) that I'm installing in my Cozy Mk IV.

Hope this helps.

PS: You can cross-over AN O-ring p/ns to M/S p/ns here:

http://spenceraircraft.com/hardware/o-rings-seals-gaskets/ms28775-006-o-ring-packing-preformed-hydraulic-109-119-id-alt-part-an6227b1-an6227-1.html

AN6227-1 = MS28775-006 

AN6227-5 = MS28775-010

Regards,

James

 

 

Scott m:n 4200 park brake valve #2.tiff Scott m:n 4200 park brake valve #1.tiff

Edited by JamesRussell
Added files after becoming a member.
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  • 10 months later...
On 2/3/2019 at 7:59 PM, MinneMooney said:

Can anyone identify this parking brake valve that’s on my ‘65 M20C?

 

47B8AD66-33E1-4FD3-8455-1EBBC2BA3233.jpeg

 

Sorry for the thread bump, but wanted to share.  I had the exact same question and decided to take mine apart today since it was leaking -- internals are 100% the same as a Scott 4500.  Since the part number for my 68 says 4500A1, and looks like this and not the rectangular body posted earlier, I hypothesize that they were originally cast and switched to machined at some point after the early 68s (I am 68-0008).

Used the o-ring specified in the manual screenshot posted on page one and so far, no leaks with a filled res on my workbench!   I bought a brass dentist pick off amazon per previous poster and, while it took a while, I got the o-ring out and swapped in about 30 min.

Also, for my knowledge, what do you guys and gals put on the AN fuel / hydraulic fittings when putting them back together?  Some sort of anti-seize or sealant?  I'm thinking of the white plumbers tape you use in your house, but know you wouldn't want to use that on an airplane in case it started to come apart and contaminate your system -- do you need anything since the fittings are tapered?  I was going to ask my A&P tomorrow when he helps me put it all back together, but I'm curious what y'all use so I can learn me some :)

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Compression Fittings are designed to work with no added sealants…

Pipe threads are designed to use Teflon tape… Conical in shape… often marked NPT (national pipe thread)

There is one place where Teflon tape gets used in a Mooney…

But, I forgot what made that unique…. :)

 

PP thoughts only, check with your mechanic, or wait for one to arrive here…

Best regards,

-a-

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  • 1 year later...

Thread bump. I just removed my 4500A. Neither I nor my mechanic have ever rebuilt one.  It was not immediately obvious how the shaft is released from the valve body but I did not spend a lot of time on it.  I have the parts schematic, but cannot find a manual that covers disassembly and reassembly. Any firsthand experience would be greatly appreciated.

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