Rear Brake Reservoir Hose, Replace?

[DaveP]

I have removed the brakes from the 1981 GS650L to clean and reinstall with new brake hoses. The hoses I just took off were dated 4/81, so still original equipment. Brake fluid was dark brown too, but only a bit of sediment, no chunks.

I am wondering if it is necessary to replace the hose between the rear reservoir and master cylinder. The parts fiche diagram shows this as Item 19 and Part No. 69731-34200, but it does not seem to be a part that is carried anymore.

Hose size and type if replacement is required?

Thanks,
Dave

[rudeman]

Just find some hose that will withstand constant contact with brake fluid and use it. It's not under any real pressure; it just carries the fluid to the master cylinder.

[eil]

If the hose is in good condition and is free of cracks and whatnot, you can reuse it. It's not under pressure like brake lines are and I've never heard of them failing suddenly. Inspect it along with the rest of the bike on a semi-regular basis and it will be fine.

[DaveP]

Does 3/8" ID sound like the right size? This is my measurement with a tape measure.

The existing hose seems fine, but I haven't been able to find anything local for a replacement either. I did find this vendor on Ebay: http://www.ebay.com/itm/3-8-ID-REMOT...-/330576924784. He also has 5/16" ID.

[rudeman]

3/8 SOUNDS close. To be certain take the hose to an automotive parts shop and have them match it up.

[8ball]

Bear in mind that most of the hoses you'll find at the parts store are not resistant to brake fluid. Even gas line isn't. You will want something in the lines of Tygon tubing (you can get it from Kurveygirl.com).

[rudeman]

Bear in mind that most of the hoses you'll find at the parts store are not resistant to brake fluid. Even gas line isn't. You will want something in the lines of Tygon tubing (you can get it from Kurveygirl.com).

Exactly, you should specify, in this case especially, that you'll be using it to carry brake fluid.

[DaveP]

3/8" appears to be the winner. 5/16" drill bit drops right in to the original hose and 3/8" fits snug below the area that was already expanded by the reservoir nipple. The rib on the nipple measured 7/16" or 11 mm. The main nipple slightly larger than 3/8", roughly 10 mm.

I was aware of the need to have a hose specifically for brake fluid and the Tygon name helped a lot. The kurveygirl.com site only carries up to 5/16" ID though, so still looking...

[Agemax]

Any EPDM rubber (just like a radiator or heater hose) is compatible with all brake fluids.

[DaveP]

Thanks again for the EPDM hose type. Local auto parts store has Prestone Radiator Overflow Tubing which is 3/8" ID EPDM hose. $1.99 for 2'. This hose is good for 25 psi and there shouldn't be any pressure in the reservoir hose.

[DaveP]

Still wondering if I bought the right thing. Went to Autozone this morning and asked for 3/8" hose that would resist brake fluid. The gave me a 1' piece of hose, ArmorMark 50280-25, that says it meets SAE J1532. Looking up that specification indicates that this is an transmission oil cooler hose.

I'll be using Rotul DOT-4 brake fluid.

[Agemax]

it will be fine. SAE J1532 covers brake fluids as well.

[srg]

Looks like you found some tubing. For the future, I've used mcmaster.com for a lot of stuff like that.