Mechanical seal options

1449 Views 47 Replies 10 Participants Last post by Meadowlark, 13 d ago

Rollinwinona

Discussion Starter · 2 mo ago

I have a 1981 gl500, it's got the signs of a mechanical seal failure. Anyone here have any luck by fixing this by only replacing the polo mint? I just ruined the new Yamaha seal when I was trying to pull the guts out and hoping when I get into the bike I may find I can clean the surface of the existing seal and using the new polo mint.
Asking cause I'm hoping to not spend another 50$

1 - 20 of 48 Posts

Randall-in-Mpls

· #2 · 2 mo ago

Welcome to the forum!
The ceramic and graphite(?) surfaces wear into one another, so the likelihood that matching new to old would be successful is low, I think. It's worth a try. At least it will give you something to do while the replacement is in transit.

Randall-in-Mpls

· #3 · 2 mo ago

Would that be Winona, MN?

Meadowlark

· #4 · 2 mo ago

Rollinwinona said:
I have a 1981 gl500, it's got the signs of a mechanical seal failure. Anyone here have any luck by fixing this by only replacing the polo mint? I just ruined the new Yamaha seal when I was trying to pull the guts out and hoping when I get into the bike I may find I can clean the surface of the existing seal and using the new polo mint.
Asking cause I'm hoping to not spend another 50$

You might get lucky... My mechanical seal was leaking every time I warmed the bike up, so I got all the parts on hand and prepared to do the job. But, my first step was a thorough cleaning of the enitire cooling system with a chemical radiator flush (Prestone brand). I flushed the sytem with the cleaner and followed with plain water a couple times. during the last warm up after this, I noticed the seal had stopped leaking. That was just a few weeks ago and maybe 50 miles or so with several warm up cycles and the leak has not returrned. Good luck and YMMV>

Reactions: 1

D-Fresh

· #5 · 2 mo ago

$50?
Mechanical Water Pump Seal for Honda CX500, GL500, CX650, GL650 – Murrays Carbs

He's a member here also.

Reactions: 1

Sidecar Bob

· #6 · 2 mo ago

I was about to look up Murray's seal but you beat me to it ;-)

Welcome to the forum. Please add your location and your bike's model and model year to your profile so that you don't have to remember to tell us every time and we don't have to keep asking when you forget (see Forum Settings link in my signature).

And welcome to the world of antique vehicle ownership (they own us, not the other way around). Your bike is about 4 decades old and may or may not have had all of the maintenance necessary to keep it safe & reliable so it is highly recommended to download the Factory Shop Manual for your model (available through the CX Wiki - link in my signature) and go through all of the service procedures, regardless of whether your bike has reached the specified mileage.
Note that while aftermarket shop manuals are pretty much necessary for people without factory training to work on a lot of makes & models of bike the FSMs for the CX/GL500/650 family of bikes are so well written & laid out that the FSM is really the only book you need and and even the best aftermarket books are secondary references at best.

I also recommend looking on all rubber parts with suspicion because rubber does not age gracefully. Check the date codes on your tires and replace them if they are over 5 years old no matter how good they look & feel (old rubber simply cannot flow around the irregularities in the asphalt well enough to grip, especially if it is cool or wet). The original rubber brake lines should be replaced every 2 or 3 fluid changes (= 5 or 6 years) so if your bike still has them I recommend shopping for modern stainless braided ones (they last practically forever and double the life of the fluid). And don't forget things like the rad hoses and the boot between the engine and swingarm (they can crack on the bottom where you don't see it).

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Rollinwinona

Discussion Starter · #7 · 2 mo ago

Meadowlark said:
You might get lucky... My mechanical seal was leaking every time I warmed the bike up, so I got all the parts on hand and prepared to do the job. But, my first step was a thorough cleaning of the enitire cooling system with a chemical radiator flush (Prestone brand). I flushed the sytem with the cleaner and followed with plain water a couple times. during the last warm up after this, I noticed the seal had stopped leaking. That was just a few weeks ago and maybe 50 miles or so with several warm up cycles and the leak has not returrned. Good luck and YMMV>

That's cool so you never had to open it up and do the seal then?

D-Fresh said:
$50?
Mechanical Water Pump Seal for Honda CX500, GL500, CX650, GL650 – Murrays Carbs

He's a member here also.

That looks better thanks! And is this a seal that works by taking it out of its cup and inserting into the cleaned out cup on the bike?

Randall-in-Mpls

· #8 · 2 mo ago

D-Fresh said:
Mechanical Water Pump Seal for Honda CX500, GL500, CX650, GL650 – Murrays Carbs

He's a member here also.

And known to fit. Some of the aftermarket seals spec'd to fit Yamahas are a little small for the CX/GL. Anything you get from Murray will have been vetted.

Randall-in-Mpls

· #9 · 2 mo ago

Just like the OEM seal or the Yamaha seal, it's designed to be pressed in. But you can (carefully) disassemble it for use in the Shep method.

Meadowlark

· #10 · 2 mo ago

Rollinwinona said:
That's cool so you never had to open it up and do the seal then?

That's right. I may still have to do it at some point, but for now, it is not leaking.

Rollinwinona

Discussion Starter · #11 · 2 mo ago

Meadowlark said:
You might get lucky... My mechanical seal was leaking every time I warmed the bike up, so I got all the parts on hand and prepared to do the job. But, my first step was a thorough cleaning of the enitire cooling system with a chemical radiator flush (Prestone brand). I flushed the sytem with the cleaner and followed with plain water a couple times. during the last warm up after this, I noticed the seal had stopped leaking. That was just a few weeks ago and maybe 50 miles or so with several warm up cycles and the leak has not returrned. Good luck and YMMV>

Meadowlark said:
That's right. I may still have to do it at some point, but for now, it is not leaking.

Hi is that standard procedure to run the system clean before starting

Meadowlark

· #12 · 2 mo ago

Rollinwinona said:
Hi is that standard procedure to run the system clean before starting

It just made sense to me.

Rollinwinona

Discussion Starter · #13 · 1 mo ago

Meadowlark said:
It just made sense to me.

So I finally got in there and was pretty simple, the old seal in the cup looked perfectly fine as did the white mint seal but I had a new mint so I put it in and buttoned everything back up and at first it seemed to be not leaking however after a few starts and short runs around town It still leaks I'm gonna take it on a long ride and see if it seals up....cross fingers, thing I don't get is how fine the seals looked when I got in there is it possible the leakage from the weep hole is from another source?

DouginEasternWashington

· #14 · 1 mo ago

No

reclinedrelic

· #15 · 1 mo ago

It is possible for coolant to leak between the engine block and the seal cup, between the seal cup and the rubber bellows, through a perforation in the rubber bellows, between the carbon face and the ceramic face, past the copper crush washer under the dome nut. Run out on the end of the camshaft can cause the seal to leak.

nolimitz

· #16 · 1 mo ago

reclinedrelic said:
It is possible for coolant to leak between the engine block and the seal cup, between the seal cup and the rubber bellows, through a perforation in the rubber bellows, between the carbon face and the ceramic face, past the copper crush washer under the dome nut. Run out on the end of the camshaft can cause the seal to leak.

in other words replace the seal and polo mint at the same time. It takes about twenty miutes longer after you have the cover off to Shep the seal

Reactions: 1

reclinedrelic

· #17 · 1 mo ago

True, although the Shep Method assumes that the original seal cup was properly installed. If the seal is leaking between the block and cup shepping a seal won't fix that.

nolimitz

· #18 · 1 mo ago

reclinedrelic said:
True, although the Shep Method assumes that the original seal cup was properly installed. If the seal is leaking between the block and cup shepping a seal won't fix that.

And how many times have you seen that? Seems like it would be an easy visual while you're in there??

reclinedrelic

· #19 · 1 mo ago

I've never encountered that.

CXPHREAK

· #20 · 1 mo ago

I think that I have. The seal on the thingy leaks and aside from the original replacement I have Shepped it twice. I think it must be leaking around the cup.

I will be starting from scratch with a fresh rear cover so that it is ready to swap in when I get to it.

A small but persistent annoyance.

And I doubt you could see this even with the impeller removed.

Reactions: 1

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