Leak in front brake switch and by the caliper

[alexdecker]

Hey all

Chasing down a front brake leak. The bike has somewhat new steel braided brake lines. But I have a leak at the switch and all the way down at the caliber.

When looking at spare parts, I can see that by the switch, there is a stainless steel washer. Is that the only thing sealing this thing? No rubber or copper seals?

Also, by the caliper, it would seem I have a leak. The steel lines just screw directly into the caliper with no seal at all either. How can I fix a leak in that area? (see picture)

- Alex

[Bryanj]

They should be soft alloy washers not stainless and can be replaced by copper at bot switch and union screwed into caliper, as to the bleeder if that is damaged replacement is the only option, what bike is it

[Laverdaroo]

Yeah, with Bryan, you’re missing the copper/ally washers either side of the banjo’s and at the calliper. If you haven’t got any, ring HEL AT Exeter, they’ll post em to you super quick and should be a couple of quid


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[Athame57]

I had this issue years ago, in my case all I had to do was tighten the switch properly, I can't think why it took me a couple of weeks to notice but it was dangerous, front brake needed pumping of the lever to work  now and then. I bled the brakes but it didn't help. But what I then discovered was that over time brake fluid had been getting sprayed at the front left overhang on the fuel tank, spoiling the paint work, it is a potent paint stripper too.

[alexdecker]

Thank you all for the replies. The leak by the switch seems very minor. I don't need to pump the lever to make the brake work. But when I use the brake 3-4 times, a tiny drop of fluid will leak from the switch. I will try and see if I can tighten it a bit and maybe that helps.

I was looking at this spare part list (https://www.cmsnl.com/honda-cb550f2-super-sport-550-four-1977-european-direct-sales_model17122/partslist/F05.html) and the washers (part 17) just seemed like regular steel ones - that's why I got a little confused.

The connection to the caliper pipe inlet is still a bit of a mystery to me. Maybe it's just broken. The part list doesn't say it needs a crush washer, so I don't know how to seal it. Why is there no crush washer here?

- Alex

[Bryanj]

The caliper does not originaly have a crush washer as the original metal pipe seals on conical surfaces, but you have different fittingd and may need the washer

[alexdecker]

How often would one replace braided steel lines?

[McCabe-Thiele (Ted)]

How often would one replace braided steel lines?

I would expect a good quality normal flexi-hose  to last betwwen 10-15 years/100K miles  unless damaged in some way during use. Good Quality Braided hose should be similar or better I would have thought.

[alexdecker]

Does anyone know a good place in Europe to get braided lines for a CB550F2 from 1977? I am getting lots of google hits from the US and UK, but none from Europe.

[McCabe-Thiele (Ted)]

Personally I see little justification for using anything other than the original set up for normal road use  - a short metal brake pipe & a normal hose.

[alexdecker]

Personally I see little justification for using anything other than the original set up for normal road use  - a short metal brake pipe & a normal hose.

I am actually contemplating switching back to the original setup. But CMS does not have every part in stock, so I am hunting for parts right now. Denmark is not a good country for this hobby. We don’t have that many people in the craft and spare part dealers etc. it’s a little annoying!

[alexdecker]

Do anybody know and can give me the stock length of the upper and lower front brake line for the CB550F Super Sport models? Supposedly they are slightly different than the K models.

[Bryanj]

You can get both hose and fittings from ebay and make your own, if you want to use the final metal pipe you will need a different fitting, i have most of the bits to hand

[deltarider]

Personally I see little justification for using anything other than the original set up for normal road use  - a short metal brake pipe & a normal hose.

Same here. Hoses on a CB500/550 are very short and I doubt ss lines will make much difference. I still run the same hoses, bike got at the assembly line in around 1976. No sign of wear. Just replaced the brake pump by a repro from CMSNL 45500-300-010P (€ 55,-)* and replaced the pads by SBS 501HF (Street) ceramic pads. Brake pump has a very nice feel.
* Normally I opt for Honda genuine parts but friends convinced me. They judged the repro better than the original which is over € 500,-.

[Laverdaroo]

I’ve a couple of lower hoses in black finish but braided stainless steel lines up for grabs. They were  the first incarnation of my brakes on the 550 and standard length. I’ve swapped set ups and had longer lines made so these are surplus. Made by HEL.
I’ve had them on the bike and bled up but removed a few days later so I guess you could say they’re 2nd hand but mint condition.
They connect to the end of the solid metal brake line after the calliper and run to the brake switch/splitter on the bottom yolk.
Drop me a pm if interested Alex


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