Shimano R8020 Hydraulic Query

Trox · 23 Oct 2018 at 21:54

I don't have much experience with hydraulic road brakes so I'm wondering if a tiny amount of oil under the hood normal?

Only reason I'm asking is both my levers are doing this from the seal and a pin that goes straight through.

It's not a huge amount but notable after a ride.

Image here for example, https://photos.app.goo.gl/b7Vi2ms4hb9iEEtV9

Trox · 24 Oct 2018 at 10:50

Jonny ///M said:
Haven't worked on enough to know if it is a major issue with them but I'd class fluid leaking as an issue.

I did work on a R7020 lever that was leaking oil out of the front torx bolt/washer setup.

Dry it all off and cable tie the lever to the bar tight over night and if the wheel can spin in the morning you know it has lost pressure. Put a bit of paper under to catch drops too. Did yhat today to work out why a 785 was losing pressure.

So I done the above over night and checked the brakes this morning. Everything seems fine wheel was still locked on and no sign of oil under the hoods.

I can only assume when the brakes are hard on there's no pressure is at the levers only the caliper?

I've released the brakes which still feel really good, if not better. I'll check after work tonight for signs of oil under the hoods.

Hopefully not, but I suspect there will be a tiny amount again.

Jonny ///M · 24 Oct 2018 at 10:59

Keeping pressure in them overnight is just checking from the lever to caliper, high pressure you could say?

It may well be a leak from the reservoir which isn't under any pressure or even residual fluid from a bleed when it was assembled?

Trox · 24 Oct 2018 at 11:23

That's what I'm hoping it is, but I'm uncertain as I've cleaned it multiple times now and it just comes back. I'd have expected to see residual oil hanging around this morning if there was any.

I thought when the brake was activated pressure is pushed down to the caliper by a plunger or something, with the lever (resevoir) free of pressure. But I'm only guessing.

In my mind I'm hoping it was residual oil from the last bleed and I've cleaned it all out last night lol

I'll find out tonight, argh...

Cheers

SoliD · 24 Oct 2018 at 19:24

Is the res bolt properly screwed in?

Trox · 24 Oct 2018 at 20:37

Hey SoliD, yea it's on tight with no sign of any leak coming from it.

I got home tonight and checked under the hoods and found nothing. I done a trainer road session and afterwards I checked again and noticed just a small dot of oil on the hood.

I might be paranoid but it's still on my mind that there's an issue, going to give it a couple of weeks as I really don't want to strip down the bike.