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Old 05-11-2010, 08:23 PM   #1
Zagando OP
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Joined: Sep 2007
Location: EL18 Rockport, TX
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Question Replacing K75S (w/ABS) brake lines with stainless lines; bleeding question:

Am about to replace the original rubber brake lines on my '94 K75S with brand new Spiegler stainless lines (yippee!).

My main procedural question:
When I bleed or remove the old fluid should I start from the ABS modulator bleed nipples or leave those completely alone? I am only installing new lines, not any master cylinders or ABS components.

Maybe best to bleed from the caliper bleed nipples, run some fresh fluid through the system, remove the old lines, then install the new lines, fill/bleed with fresh fluid (again from the caliper nipples ONLY) until no more bubbles or old fluid remnants are pulled out of the system? Sound right, folks?

Or should I also bleed from the ABS modulators as well? If so, before or after I bleed from the calipers?

Which way should I proceed, please? Hope to find out soon as I've got all my tools (Mity Vac, big bottle of DOT4, Spieglers, torque wrench, crush washers, etc. etc.) ready AND three days in a row off from work.
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2003 Honda Ruckus "Rucca"

ex: '94 K75S "Berlina" '92 R100GSPD
'85 K100RS '73 R75/5 '65 R60/2
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Old 05-11-2010, 10:14 PM   #2
dtalk
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Speaking from hard experience on that bike: I strongly recommend that you just let a shop do it. It is very, very difficult to properly bleed that system. You have a lot of hard pipe under the tank that changes direction a few times, plus both modulators, and yes, you have to bleed at every nipple. Getting all the air out of the miles of piping is hell on earth.

Furthermore, bleeding using the vacuum method never worked well for me; I don't think you can generate enough suction that way. If you use the old-fashioned manual lever-squeezing method, you risk introducing leaks, as you will have the old cylinder making contact with corroded areas that it normally doesn't touch.

The "right" way to do these bikes is with a pressure bleeder, which can be built out of a garden sprayer, but what is your time worth?

Simple bleeding to refresh fluid isn't too bad, but getting air out after replacing parts is just. Not. Worth. It.

If you can swing the labor cost, do yourself a favor and pay for it ... life's too short.
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Old 05-11-2010, 11:36 PM   #3
Zagando OP
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Thank you for the solid advice, Dtalk. Although I also happen to have an unused pressure sprayer from the hardware store on hand I think the idea of having a shop with a power bleeder and plenty of experience with this sort of situation is best. I hear you loud and clear.

My nearest (and basically only) option is our local Suzuki dealer about 30 miles down the hill from me---but I could ride down there, remove the seat, side covers, gas tank and part of the fairing right before I deliver the bike to them to save a bit of the huge labor cost.

Although they probably won't allow it, I could try to work a deal with them where I help them as much as possible since I'm fairly familiar with my bike. There's hardly any BMWs around here so they might welcome a bit of advice, torque values and so on.

At any rate, I suppose I'll just bite the bullet and go this route---thanks for saving me finding out what a bitch it is before I almost took the plunge...
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2003 Honda Ruckus "Rucca"

ex: '94 K75S "Berlina" '92 R100GSPD
'85 K100RS '73 R75/5 '65 R60/2
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Old 05-12-2010, 08:11 AM   #4
dtalk
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Quote:
Originally Posted by Zagando
At any rate, I suppose I'll just bite the bullet and go this route---thanks for saving me finding out what a bitch it is before I almost took the plunge...
You mighta got as far as I did -- back to 70-80% effective, and then after inventing many new words, rode to the shop to finish the job ....

I just took a look at your paint thread over at MOA -- holy crap, that is sharp! Some awfully nice work you did. But take my opinion with a grain of salt, cuz I thought the yellow looked nice too.
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Old 05-12-2010, 12:54 PM   #5
dtalk
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Quote:
Originally Posted by dtalk
Furthermore, bleeding using the vacuum method never worked well for me; I don't think you can generate enough suction that way.
I just found your other thread over there ... thanks to Don E's post, I remember now what the problem was; it's velocity of fluid that you need to get that done correctly. That's what the pressure bleeder does for you.

Don is the K-King; he knows what he's talking about.

I just checked my parts bin, and I see that I still have the modified brake reservoir caps that I made as part of my attempt at pressure bleeding on that bike. If you decide to go that route, you will need those caps. I'll send them to you for just the cost of shipping if you want.
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Old 05-12-2010, 03:28 PM   #6
Zagando OP
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Thumb Can use those caps as I'll give it a go with a pressure bleeder

PM sent, thanks again, Dave!

PS: The yellow looked good from a distance but the bike had a couple of tip overs and attempts to cover them up by a PO were pretty amateurish; it wasn't quite as pristine as it seemed.
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=Zagando=
2003 Honda Ruckus "Rucca"

ex: '94 K75S "Berlina" '92 R100GSPD
'85 K100RS '73 R75/5 '65 R60/2
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Old 05-12-2010, 05:55 PM   #7
dtalk
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Acknowledged.

I hope you have better K-arma than I did when I tried it.

Cheers!
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