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Ever since I bought my 1999 Aspencade, I noticed that the brakes (front and rear) were mushy. I just got through doing a full brake bleed on all 3 systems doing a full flush using speed bleeders to help make it quicker/easier and using Dot 5.1 fluid to replace it with in both cylinders. The pads currently on the bike are OEM Honda and all 3 have at least 50% wear left on them and none are unevenly worn. But when I did the bleed, I didn't notice any major bubbles and the calipers seem to be working fine. I don't own a micrometer (but I'm borrowing one next week) to measure the rotor thickness but even after the bleed, they're still mushy, especially when compared to my 2002 ST1100 and a 2020 Goldwing I borrowed while the shop did an inspection on mine yesterday.

Does anyone have any information on what might be causing the brakes to be so mushy? Also, both the handle and pedal have to travel at least 50% before any biting occurs whatsoever. As far as I know, there's only two possible culprits left, the rotors and the calipers, both are expensive, although calipers is something I could at least do myself. (I don't think I could do the rotors, I don't have any way to lift the bike up nor do I own any breaker bars, etc to loosen the large bolts holding the wheel/rotors in place)

I'm not expecting it to behave exactly like my 2002 ST1100 or the 2020 Goldwing, as I know those braking systems are vastly different (although the 2002 ST1100 shouldn't be too different, although it's not linked like the Goldwing) but they just don't feel right and I don't have any confidence in my stopping power. I know with the ST1100, one of the things they suggested on the forums there was replacing the brake lines from the master cylinder to the caliper with steel braided lines because they said the originals tended to expand and cause the brakes to not work well. Is that also a possibility on the Goldwing? If so, is the solution the same?

Stay safe, God bless,

~Mark
 

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Steel covered lines will make a small difference, one common problem is the sliders the calipers move on tend to sieze up as do pistons in the calipers. Twin piston calipers can have one sieze whilst the other stays free.
Repair kits are available and not too difficult to fit, i recently put up a post on how the seal works, personaly i would replace any piston that has any corrosion especially pitting-----you only got one neck!
 

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As long as the calipers are not leaking or sticking there is nothing wrong with them. The thickness of the pads and rotors should have no effect on the firmness of the brakes. Other than air in the lines the hoses are the only thing that would cause the brakes to be soft.
 

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Really only two (2) brake systems …
1) … there is the right front caliper to "handle bar" mounted master cylinder ...
2) … and then there is the left front caliper on a long line (attaches to side of rear MC) to the "rear" or "foot" master cylinder which also activates the rear brake caliper off a separate port (located at rear most end of the rear MC). The rear master cylinder supplies approximately 60% of it's effort to the left front and approximately 40% of it's effort to the single rear caliper by means of internal build (it's built much like a miniature car dual system MC).

You bleed the right front caliper & handle bar MC separate from the foot MC. When bleeding the left front caliper and rear brake caliper, do … rear … left front … then do left rear again … (and I have then done left front again too). Never let the reservoir go empty while doing it.

Use only DOT 4 rated fluid from a sealed container.

Good time to do clutch MC & slave too, I think.

The longest line of all is from foot MC to left front brake caliper, and it rises then drops at each end so there is a ready made opportunity to leave air in the high spot. If … (after bleeding the "rear" or "foot" master cylinder and left front & rear calipers) it's still soft, do it again.
 

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As the lines age they get soft and flexible. When you apply the brakes you only push a small amount of fluid under pressure.The soft lines expand and in essence become larger using up some of the displaced fluid. The harder you push the more they expand. That is what gives the "mushy" feel.
Some go to a steel braided line. If you just replace the line with OEM there will be a significant difference. There are several kinds of steel braided lines. One type uses a conventional line with a steel braided cover. These hoses will not carry any more pressure as the steel braid is there to protect the hose from abrasions and damage. The hoses that use steel braid as part of the internal structure are typically rated for higher pressures than a fabric braid.
The DOT 5.1 brake fluid is a step up from the DOT$ and compatible with an even higher boiling point. DOT 5 is the silicone based that we have to avoid. :)
 

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The DOT 5.1 is what the Harleys use. I have always read the DOT 4, and DOT 5.1 were not compatable with each other, so I never tried it. If any DOT 4 was left in system, that could be your problem. I like the sped bleeders though. A lot of brake fluid can be run through system in a hurry. I believe the DOT 5.1 needs to be replaced with DOT 4 again. (NOT what you want to hear.)
gumbyred
 

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Gumby,
As strange as it sounds DOT 4 and DOT 5.1 are compatible. DOT 4 and DOT 5 are not compatible. Here is from a website. :)


Since DOT 4 and 5.1 are both glycol-based brake fluids they are compatible with each other, which means they can be readily mixed without harming your brake system. It is important never to mistake DOT 5.1 (glycol-based) with DOT 5 which is silicone-based and should never be mixed with any other DOT fluid.
 

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I always heard to only use DOT 3 or 4. you can gravity bleed the system, I have done that with great success,. Might take longer and you have to keep an eye on the reservoir so it doesn't go dry but I have had great success doing it that way, and you only need 1 person and nothing else.
 
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