honda goldwing gl15000rear brake master cylinder


Information and questions on GL1500 Goldwings (1988-2000)
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wingdings
Posts: 492
Joined: Mon Feb 10, 2014 12:48 pm
Location: mells , England, United Kingdom
Motorcycle: Honda Goldwing gl 1989

honda goldwing gl15000rear brake master cylinder

Post by wingdings »




hole in cylinder bottom
hole in cylinder bottom


do not buy from ebay until you check the banjo hole bottoms on the cylinder this a pic from a dealer its pup part
do not buy from ebay until you check the banjo hole bottoms on the cylinder this a pic from a dealer its pup part



Hi - Folks just found out what's wrong with my braking system on my Honda Goldwing GL 1500 1989 model , while investigating a spongy back brake pedal and doing all the usual stuff bleeding !! rebuilding the rear brake caliper etc - all to no avail by the way - I finally ended up stripping down the bike to gain access to the rear master cylinder .

After removing the part and stripping down the cylinder and removing the banjo bolts from the cylinder and looking down the bore's - Shock horror !!! down one of the bores it was completely holed though - the small hole that should have been there !! was now a massive hole !! . further more Honda do not make this part anymore too !! and when they did the cost in the UK was £400 .

This left me no choice except to hunt around for a good second hand one - Beware too !! if you go looking on ebay - the ones on there can be bad too !! I nearly bought a duff one of a seller on there ( see pics above buyers beware !! ) - if I had not asked for pics of the banjo blot hole bottoms - I would have wound up with a duffer so best advise hear -is don't matter if it looks nice !! does it work ?? . As the ones I looked at not one showed pics of the bore bottoms so it may have looked nice but there was no way of telling if it worked ?? . buyers beware !!.

If the seller don't send you the pics you ask for then don't buy the part from them !! I was lucky to find a guy in the USA - that was prepared to unwrap the cylinder and take the pics I asked for the part is now on its way too the UK

looking at the Cylinder its a great pity that someone out there cannot offer a refurbishment service on the banjo inserts they would make a fortune out of it too now Honda do make the part anymore and it would only take a small work shop with the right tools to refurbish them - just needs to find out where the inserts could be made or bought from .

Lastly - if you have a spongy brake pedal - Get it sorted or it could be your neck next time !! and if you have done everything like I did - and its still spongy - strip the rear master cylinder down - look down the bore to the bottoms - bet you find like I did not a small needle hole in it but a big gapping hole where the bottom had worn out completely not good at all .

hole in cylinder bottom
hole in cylinder bottom


do not buy from ebay until you check the banjo hole bottoms on the cylinder this a pic from a dealer its pup part
do not buy from ebay until you check the banjo hole bottoms on the cylinder this a pic from a dealer its pup part



Attachments

cylinder of my bike note the big  hole in the bottom of the banjo blot hole
cylinder of my bike note the big hole in the bottom of the banjo blot hole


cylinder of my bike note the other banjo blot hole this is what it should look like no big hole in the bottom
cylinder of my bike note the other banjo blot hole this is what it should look like no big hole in the bottom




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wingdings
Posts: 492
Joined: Mon Feb 10, 2014 12:48 pm
Location: mells , England, United Kingdom
Motorcycle: Honda Goldwing gl 1989

Re: honda goldwing gl15000rear brake master cylinder

Post by wingdings »


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ct1500
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Re: honda goldwing gl15000rear brake master cylinder

Post by ct1500 »

If they are both front/rear outlet hose ports I would expect the front brake port to be larger which would aid the typical front brake bias 60/40 or thereabouts.
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Elmobile
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Joined: Sat Aug 22, 2015 8:35 pm
Location: Bridgewater, Nova Scotia, Canada
Motorcycle: 1990 GL1500SE

Re: honda goldwing gl15000rear brake master cylinder

Post by Elmobile »

This port is for the rear caliper. It is the pressure "regulated" one.
Mine was like that when I rebuilt it a while ago... I am confident that it is the original master cylinder. So if it is good enough for Honda to let it go, it is good enough for me.
Clearly a manufacturing error as the machining should not go that deep and open the bore... However when you think about it the amount of fluid displace is determined by the piston bore/travel, not the size of the port orifice. The amount of pressure applied to the piston caliper will remain the same, small or bigger hole!



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