Firmer than expected front brake lever after Spiegler installation

[aigram]

I've recently installed the Spiegler brake/clutch line kit on my '89, and I'm impressed at how firm the front brake lever now is after a thorough bleeding of the system.
For my taste, it's too firm. The travel is such now that I really cannot modulate the brake pressure; They start to firmly grab after only about an inch and a half of lever travel. Anything beyond that and it seems like the brakes want to lock up the front tire. Does anyone have experience with this? How can I get some more friendly feel back in the system?

[FJmonkey]

I like a little air in my rear brake system so it is less sensitive. Might not be good for front brakes if they get hot for any reason. 

[Pat Conlon]

I'm not a fan on introducing air into the system.
As Markus said, it does work on my rear brake but I would never consider it on my front brakes.

A second option: Convert over to DOT 5 silicone brake fluid. It would mean a complete disassembly and cleaning on your system to remove all traces of DOT 3/4. The DOT 5 will give you a slightly softer feel at the brake lever. Because DOT 5 is non hygroscopic (does not absorb water) I would not recommend it in a wet climate.

A third option (best):  The stock FJ master cylinder piston diameter is 5/8" (it's cast on the body) or 16mm.
If you want a better feel at the brake lever, (longer travel) change your master cylinder out to a FJR m/c which uses a 15mm piston or a FZ1 m/c which uses a 14mm piston. Both are plug and play with your '89.
You will have better control at threshold.

Cheers

[aigram]

Hey Pat,
I'm a big fan of option 3. I went to Partzilla and looked at the Front Master cylinder diagram for a '05 FJR. The lever assembly and M/C assembly together are only $185! Can it be that easy? There is a front stop switch assembly that appears related in some way to the M/C assembly, so that's a bit nebulous.

[Pat Conlon]

No reason to buy new $$$$
Buy them used on FleaBay....they are plentiful and cheap

For example FJR https://www.ebay.com/itm/FJR-1300-Front-Brake-Master-Cylinder-from-2004-Yamaha-/353069289269

FZ1: https://www.ebay.com/itm/2006-Yamaha-FZ1-front-master-cylinder-lever-/273177297614

I think you will like the smaller 14mm m/c off the FZ1 the best.


If you are worried about buying used...buy a rebuild kit and replace the seals...and call it a day.

Cheers

[Millietant]

+1 for the FZ1 master cylinder, great feel (especially with the blue spot calipers) and you get a span-adjustable lever in the mix too 

[CutterBill]

.. Because DOT 5 is non hygroscopic (does not absorb water) I would not recommend it in a wet climate.

Pat, did you really mean that? Or is that a typo? The fact that DOT 5 fluid is non-hygroscopic means it would be ideal for a wet climate. (Actually, it's ideal for any location but that's another discussion.)
Bill

[Pat Conlon]

.. Because DOT 5 is non hygroscopic (does not absorb water) I would not recommend it in a wet climate.

Pat, did you really mean that? Or is that a typo? The fact that DOT 5 fluid is non-hygroscopic means it would be ideal for a wet climate. (Actually, it's ideal for any location but that's another discussion.)
Bill

Hi Bill, yes, that's what I meant.
Water sneaks into your hydraulic system, past the seals, where it's absorbed by DOT 3/4. When you change your fluid out, you also take out the absorbed water, you are good to go..
With DOT 5 when it's not absorbed, water still gets in, accumulates and pools at the low spot of the system.(water is heavier than silicone)
Very evident with the clutch slave, water pools at the bottom of the bore pitting the aluminum bore and rusting the steel piston.
With DOT 5, just because you flush you brake fluid out *does not mean* you have taken the water out with it.*** Think about where the bleeder port is located....up high where the air accumulates....not down low where the water pools.

Therefore, if you live in a wet climate or do a lot of wet riding, you want a brake fluid that absorbs water.
That way you can easily remove the water when you flush out the old DOT 3/4

Water is getting into your system, one way or another.

Cheers

*** I have DOT 5 in my '84 and I have a special technique for bleeding that helps address any pooled water...then again, I live in the desert.

[FJ_Hooligan]

I may be the exception.  I live in North Texas where the summer humidity can get very uncomfortable with lots of moisture in the air.

When I swapped over to DOT 5, that fluid remained in the front brake system until I did the 17" front wheel upgrade and caliper change to monoblocks. 

I split the stock calipers to look for any sign of corrosion.  None to be found, bores nice and shiny like they had just been machined.

Amount of time between DOT 5 fill and caliper change = 14 YEARS.  Never bled or even removed the master cylinder cover during that time.

[Pat Conlon]

Do you ride in the rain David?

At the 2011 soggy WCR in Hayfork, after 5 days in the rain, I had water in my systems.

If I stay dry, I change my DOT 5 every 2-3 years. Do I really need to? Prolly not....

[CutterBill]

Pat... that is so strange. DOT 5 silicone brake was originally developed for the military because they were tired of moisture-induced corrosion of the brake system internals. Switching the fleet over to DOT 5 stopped the corrosion. 

Your experience is at odds with the military's. Very strange...
Bill

[Pat Conlon]

....Switching the fleet over to DOT 5 stopped the corrosion. 

Nope, sorry, not buying it... https://tinyurl.com/yd3tmtxw

[aigram]

It seems that what Pat is saying is that inevitably some air & moisture will find it's way into the system, over time. This is a given.
DOT 5 is hydrophobic; That moisture has to collect somewhere, and since it cannot be close friends with DOT 5, it will pool in the lowest part of the system.

No DOT 5 conversion for me this season, but I bet that FZ1 M/C is going to work it's way into my mailbox this year

[CutterBill]

Pat, what you say makes sense but other long-term users of DOT 5 disagree with you.  I found an interesting discussion in the forum of the American Antique Car Club...
https://forums.aaca.org/topic/318446-change-brake-fluid-from-dot-3-to-dot-5/

If you read the discussion, they are fairly even divided between the swear-by-it group and the never-use-it group. So who is right? Beats me. I will say that I will almost put up with any problems that DOT 5 fluid might create, just so I don't have to deal with DOT 3 & 4 fluid being such a good paint stripper. I once had to tear down a perfectly good FJ1100, just so I could repair the paint damage from a leaky clutch master on the frame. Ugh, no thanks...

Well, I'm running the DOT 5 in my FJ's and my WR400; I guess we will find out the truth in a few years. Stay tuned...   
Bill

[FJ1200W]

....Switching the fleet over to DOT 5 stopped the corrosion.  

Nope, sorry, not buying it... https://tinyurl.com/yd3tmtxw

I've not spend much time on this subject, this is it.

I'm sticking with the old DOT 3/4 and flushing it every couple of years.

If I install a completely new system, I might consider dot 5.1.

Otherwise I don't feel there is enough of an advantage for me to make the change to DOT 5.0.