Poor rear brake when wet

[BigD_83]

OK,

Short story-

The rear brake is great when dry, but absolutely miserable when wet, as in feels like baby oil underfoot.

I *think* I replaced these brake pads when I did the rebuild (not sitting in front of my notes at the moment and my memory fails me), so let's assume I did for discussing this point. (I will be looking at replacing the pads anyhow)

Apart from worn pads, what other mechanisms could explain the good dry/poor wet performance?

I'll start off with:

1. the caliper (pin) grease is somehow washing off onto the pads/rotor- this doesn't seem likely to me

[Agemax]

if it works fine in the dry, it can only be pads or the rotor.
are thee pads glazed over, look very shiney and smooth to the touch?
is the rotor glazed over as well?
get some rough grit emery cloth and run it over the pads and the rotor, so they have a nice matt sort of scratched finish. see how they feel after that.

the only other explanation is,as you say, you are getting some sort of oil/grease contamination on the rotor

[daturat100r]

I ride my old gs rain and shine and when cold and wet the brakes are terrible so when first on the move i ride with them on hardish till they begin to bite then constantly touch them on to keep some heat in them and keep em dry,chops thru the pads quickly specially the rears but it is totally necessary

[BigD_83]

I ride my old gs rain and shine and when cold and wet the brakes are terrible so when first on the move i ride with them on hardish till they begin to bite then constantly touch them on to keep some heat in them and keep em dry,chops thru the pads quickly specially the rears but it is totally necessary

I've noticed this as well, but surely it means something is wrong. I've had other bikes in the past that never forced me to resort to this tactic.

Of course, those bikes were much newer than 30 years old at the time.

I wonder, can humidity wreak havoc by causing swelling of the seals (even new ones)?

[BigD_83]

if it works fine in the dry, it can only be pads or the rotor.
are the pads glazed over, look very shiney and smooth to the touch?

Not that I noticed last time I had them off

is the rotor glazed over as well?

No glazing of the rotor

get some rough grit emery cloth and run it over the pads and the rotor, so they have a nice matt sort of scratched finish. see how they feel after that.


I did that with the front pads, IIRC. I have some new EBC Organic pads on the way, so I'll at least have something to compare these to

the only other explanation is,as you say, you are getting some sort of oil/grease contamination on the rotor

This might require some investigation to look at whether or not I have any engine products blowing back onto the rotor

[daturat100r]

Nothings really "wrong" with them ya just gotta remember disc technology was pretty new and not completely sorted out when these brakes were fitted to these old girls.Been meaning to drill the discs on my bike and/or do a saltymonk upgrade but they been working ok since cleaning and rekitting the mastercylinders.

[bwringer]

GS brakes can and should work fine in the wet. Mine do.

What kind of brake pads are in there? Put in good modern pads if you haven't already.

[BigD_83]

Brian,

They were newer EBC pads on front and rear when I picked up the bike two seasons ago. Can't tell you much about them (break in, mileage, etc) except they had lots of pad thickness.

[WShie]

Gotta think it's your pad material. Honda had big problems with their Goldwings rear brakes in the wet at around this era. Their solution was to put a shield on the rear rotor to deflect the water.

[Toasty]

Did you bed the pads after you put them on?

[BigD_83]

Did you bed the pads after you put them on?

Looking back at it, it appears that I did not replace the pads when I got the bike from my buddy, so I can't tell you HOW they were bedded in.

I am waiting for my new pads (EBC organic) to arrive, though, and we'll see if that makes a difference.

[BigD_83]

are thee pads glazed over, look very shiney and smooth to the touch?
is the rotor glazed over as well?
get some rough grit emery cloth and run it over the pads and the rotor, so they have a nice matt sort of scratched finish. see how they feel after that.

I pulled the old pads off today and put the new ones on.


There was plenty of thickness left on the pads but there WAS a bit of glaze on the old pads, which cleared up with some easy sandpapering. The rotors also felt a bit "slick" so I gave them the same treatment.

We'll see how things go once I get these bedded.