Brake bits

bosco659

bosco659

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I went to install a shorter brake line from the master cylinder to the splitter block on the forks (custom block, dual disc brakes). It all seemed simple until someone one wasn’t watching and let the reservoir go empty. I thought no big deal, I’ll fill and bleed it. Not so simple, but that’s another story. Of more importance to me is to get the banjo bolt to seal on the splitter block. Here are the washers that came off. There two copper washers with some rubber seal stuff on them and the po also put an extra copper washer on the inboard side of the banjo. I tried replacing these washers with two new copper crunch washers but it leaked like a sieve.

Maybe I need to find these rubber / copper sealing washers? I’m speculating the extra washer may have been installed to gain clearance for the banjo fitting (sits too close to splitter block). Anyone know if these were factory washers?
 

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bosco659 said:
I went to install a shorter brake line from the master cylinder to the splitter block on the forks (custom block, dual disc brakes). It all seemed simple until someone one wasn’t watching and let the reservoir go empty. I thought no big deal, I’ll fill and bleed it. Not so simple, but that’s another story. Of more importance to me is to get the banjo bolt to seal on the splitter block. Here are the washers that came off. There two copper washers with some rubber seal stuff on them and the po also put an extra copper washer on the inboard side of the banjo. I tried replacing these washers with two new copper crunch washers but it leaked like a sieve.

Maybe I need to find these rubber / copper sealing washers? I’m speculating the extra washer may have been installed to gain clearance for the banjo fitting (sits too close to splitter block). Anyone know if these were factory washers?
Click to expand...

I only have my own bikes for reference, but the factory washers on my bike had those rubber seals on them. When I rebuilt the brakes on both of my bikes, I replaced all of them with solid copper washers. I’ve never seen washers doubled like that before. Maybe some others will weigh in here too.
 
The rubber isn't swollen on those washers, so that does tend to point to 'em being correct. Not sure I like the idea of doubling the washers.... kinda doubles the places it can leak.
For a test fit, just use a single washer on one side and none on the other. If it'll snug up like that, you won't need to double up... one on each side will do.
 
I recently replaced the three original front brake hoses on my 78 special with braided lines and the splitter had three copper washers on it. The braided lines came with new banjo bolts and washers with one on the bolt at the head then a hose and washer and the other hose and washer then onto the block.
I used two lengths of clear 8mm hose each 500mm long connected from the bleeders into two jars of dot 4 brake fluid and slowly bled the total system leaving the bleeders open and topping up the master cylinder as I went. It took about one hour to do the whole job so I was quietly surprised after reading some recent posts on here.
The braided lines have made a good improvement without too much expense. Hope this helps.
 
Two things I would check:
i) The bolts aren't bottoming out thus preventing a good seal (and may explain the extra washer which gives extra clearance).
ii) The flatness of the mating face with the washers on the splitter.

What you describe sounds similar to that on the V Max (below) which is leak free using plain copper washers.

Brake Hoses Front.jpg
 
5twins said:
I've never found anything but metal (copper) washers on these brake lines, but I guess the rubber metal washer, called a Dowty washer, might be considered an upgrade.

https://www.amazon.com/Hilitchi-180-Pcs-Metric-Bonded-Assortment/dp/B07CKVYWD4
Click to expand...
Those seals use NBR (nitrile rubber), which is not compatible with brake fluid. It's for petroleum based liquids. They'll likely swell and leak.
If you're gonna go the dowty washer route, make sure you get some using butyl rubber. If it doesn't say what rubber is used, make sure it says "brake fluid compatible."
 
Old Fart - did you buy Ebay ones. I'm currently looking at ebay ones but I'm a bit suspicious because they are so cheap ($20 each). A local shop here in Adelaide quoted me $100 each - made while you wait. I need 3 because Australian delivered 77D.
Did you buy 500mm long for the bottom hoses.
Regards Ray.
 
LTGTR said:
Old Fart - did you buy Ebay ones. I'm currently looking at ebay ones but I'm a bit suspicious because they are so cheap ($20 each). A local shop here in Adelaide quoted me $100 each - made while you wait. I need 3 because Australian delivered 77D.
Did you buy 500mm long for the bottom hoses.
Regards Ray.
Click to expand...
The hose I purchased was a Russell. I believe they are a US company but wouldn’t be surprised if the items they sell are sourced from China. My bike has a non standard braking system and used a hose with removable ends. It’s more expensive to do it this was but ensures the brake line wont be twisted when installed, because the banjo fittings at the end aren’t “clocked” at the correct angle. Here’s the bits used on that hose I replaced. The end banjo pieces can be purchased straight, 35° and 45°.

C61C78DA-4AAE-49D5-830F-C41A163095E3.png
861A747D-B586-470B-BD63-8ABBE540BF34.png
 
bosco659 said:
Still waiting for fittings to arrive. On the subject of brake fluid, some recommend using DOT 4. Is this necessary on these street bikes? I‘m just being frugal as I have a new 1L bottle of Dot 3 to use up.
Click to expand...
Hi bosco,
all my part-used bottles of brake fluid say DOT3/4 on 'em, so I reckon DOT3 & DOT4 are just about the same stuff.
I think that DOT4 has a higher temperature rating than DOT3 but they'll mix together OK should you need to top up with DOT4 at any time.
NOT DOT5 though. It's what Harleys use and just like the bikes, it don't play well with others.
 
Dunno but I have motorcycle brake joints that I couldn’t stop from leaking even with new copper or aluminum washers. I bought some sealing washers (for brakes) which I believe are aluminum with a Viton donut in the middle and no more leaks. I even went so far as to try to resurface the mating parts of the brake fittings to no avail. Sealing washer did it though.
 
If you buy new brake hoses make sure they are SAE J1401 rated. That is the minimum standard in Oz. I bought two Oz rated brake hoses on ebay or aliexpress, can't remember which. Just be careful though as most aren't SAE J1401 rated.

I just use plain copper washers as they can be reused over and over. I used a banjo for connection to the caliper. However, there was insufficient space for the banjo to be fitted, so, I spun up an aluminium spacer and used a double banjo bolt, so, there are three copper washers and a spacer on my caliper, no leaks. Aluminium makes good sealing washers, so I probably could have gotten away with just the one copper washer on top of the banjo fitting.

If yours still leaks with new copper washers, perhaps the splitter block needs refacing. Simple enough job if you have a lathe or mill. If not any engineering shop should be able to reface the splitter block for you.
 
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