Nylon Filter in the By-pass Valve Plunger

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tractorfan
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Nylon Filter in the By-pass Valve Plunger

Post by tractorfan » Thu Feb 28, 2019 7:59 am

At what point did the nylon filter in the by-pass valve plunger begin to be fitted in the Selectamatic range? I have a 1967 880 and am reluctant to remove the dump valve and get into the valve chest if I don't need to.

Thank-you.

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ollek
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Re: Nylon Filter in the By-pass Valve Plunger

Post by ollek » Thu Feb 28, 2019 11:27 am

What is the problem you have with the 3-point hitch?

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tractorfan
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Re: Nylon Filter in the By-pass Valve Plunger

Post by tractorfan » Thu Feb 28, 2019 11:36 am

Hello, and thanks for your reply.

There doesn’t appear to be a problem. I’m just giving the tractor a good service as per the manual and so I thought I’d check that the nylon filter is clear, as I’m changing the oil and transmission/hydraulic filter anyway.

Thank-you.

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ollek
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Re: Nylon Filter in the By-pass Valve Plunger

Post by ollek » Thu Feb 28, 2019 1:44 pm

There is absolutely no reason to clean the filter in the by-pass valve, if the 3-point hitch is working (lifting).

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tractorfan
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Re: Nylon Filter in the By-pass Valve Plunger

Post by tractorfan » Thu Feb 28, 2019 2:13 pm

Excellent - thanks for that. I didn’t really want to go there if I didn’t need to.

philedge
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Re: Nylon Filter in the By-pass Valve Plunger

Post by philedge » Fri Mar 01, 2019 7:24 am

Cleaning the bypass valve filter was added to maintenance tasks in later versions of the 880 manual. Whether you do it or not probably depends on how well the gearbox oil and filters have been maintained in the past??
'66 880 Selectamatic rat.

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tractorfan
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Re: Nylon Filter in the By-pass Valve Plunger

Post by tractorfan » Fri Mar 01, 2019 10:01 am

Has the filter always been there, from the earliest Selectamatics, but wasn’t mentioned until later manuals? I’m only asking because I have a 1966 770 on a ‘D’ plate. There’s no mention of such a filter in the manual, but does that mean the filter isn’t there?

The 880 I’m servicing has been idle for about 10 years so I’m going through all service schedules in the manual to make sure that all is well. The hydraulics seem to be working fine but I thought that seeing as I’m going to change the oil and transmission/hydraulic filter it seemed a pity that I wouldn’t check all filters. I don’t really want to go there, so I was happy when Ollek suggested I leave it alone; it looks like a tricky job.

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ollek
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Re: Nylon Filter in the By-pass Valve Plunger

Post by ollek » Fri Mar 01, 2019 1:13 pm

The first red 770 Selectamatic had no filter. To my knowledge all white Selectamatic had the filter. I can only say: "If it works, don't touch it". Cleaning the by-pass valve filter was never a service item on later tractors, as it was discovered that it was not needed if the oil and suction filter changes were done as stipulated.

philedge
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Re: Nylon Filter in the By-pass Valve Plunger

Post by philedge » Fri Mar 01, 2019 11:11 pm

Whether or not you clean the nylon filter I would guess depends on the type of suction filter you have and how critical a working set of hydraulics are to you.

If you have an early tractor with a metal gauze strainer, then you wont get fine filtration provided by the later paper filter and are more likely to get small bits in the nylon filter particularly if maintenance has been neglected. Theres a reason DB added cleaning the nylon filter to the maintenance regime and I suspect it could be down to hydraulic problems with tractors using gauze suction strainers?? As has been said, it may not be required on later tractors but it was added to the 880 service regime and continued to be a requirement in other models well into the 70's

If working hydraulics are important to you and a breakdown away from a workshop isnt something you want, then youre probably better placed to check the nylon filter during servicing now than in the middle of a field doing something important.
'66 880 Selectamatic rat.

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tractorfan
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Re: Nylon Filter in the By-pass Valve Plunger

Post by tractorfan » Tue Mar 05, 2019 7:44 pm

I decided to go for it - just this once! All has gone well so far, but I just can't get the nylon filter out of the bottom of the plunger. Is it screwed in? Is it made from plastic?

Thanks.

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tractorfan
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Re: Nylon Filter in the By-pass Valve Plunger

Post by tractorfan » Tue Mar 05, 2019 7:46 pm

I just remembered that it's nylon :oops:

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db2d
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Re: Nylon Filter in the By-pass Valve Plunger

Post by db2d » Tue Mar 05, 2019 7:58 pm

Early ones were brass

philedge
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Re: Nylon Filter in the By-pass Valve Plunger

Post by philedge » Tue Mar 05, 2019 8:06 pm

If you follow this link
https://sites.google.com/site/deerebrow ... wn-info-ii
You'll find a 770 manual that details cleaning the filter towards the back of the manual
'66 880 Selectamatic rat.

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bedwards1966
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Re: Nylon Filter in the By-pass Valve Plunger

Post by bedwards1966 » Thu Mar 07, 2019 11:53 pm

It's down as a maintenance/service task in the manual for my 995 as well. Always thought that the paper suction filter should do enough and to leave well enough alone, but it is certainly in the manual as part of the service routine.

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tractorfan
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Re: Nylon Filter in the By-pass Valve Plunger

Post by tractorfan » Sun Mar 10, 2019 11:56 am

Well, I did it. I didn't fancy it at all, but it bugged me that I was going to change the oil and main filter but not at least check the bypass filter (even though it was working). All has been reassembled and is working. The nylon filter was fine but I had to destroy it to remove it - it was stuck at the bottom of the plunger. I purchased a new one and I've attached photos below prior to reassembly. Thanks to you all for your input.
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