'98 Wing Motor Trike - Front Brake Issue

[BradT585]

My Dad has a '98 Wing with a Motor Trike Conversion. It has had issues with the front brakes being very weak (brake lever pulls easily to the grip and has little stopping power) form the day he got it 3 years ago. I finally convinced him to trouble shoot and fix it. After some time checking it out and researching our Conclusions/Assumptions are;
1. The original configuration of the brake system was the right front caliper worked off the hand brake and the left off the rear brake system. Fact?
2. When the Trike kit was installed the line from the rear to the left front caliper was capped and the front line was split to feed both the left and right calipers. Fact?
3. The front master cylinder is not capable of feed both calipers a sufficient amount of fluid to get satisfactory braking power. Assumption!
I am hoping that someone here might be able to verify our conclusions/assumptions and, better yet, offer some advice on how to best correct this problem. Our answer, as of now, is to bypass the left caliper completely and use the hand brake to operate the right caliper only, as it did from the factory. Doing this we have a good firm brake lever that stops well short of the grip. We figure one caliper at 100% is better than 2 that barely work.  I was wondering about fitting it with a master cylinder (Valkyrie maybe) that is made to power two calipers??
Any and all comments and suggestion are welcome and appreciated. Thanks.

[Chrisj CMA]

I am fairly certain from talking to some wing owners that whichever caliper is assisted by the back brake peddle, its not the entire caliper that is operated from the rear, just one piston. 

Im no rocket scientist, but If the lines to both front calipers are sound, filled and bled properly, the "amount" of fluid should be irrelevant.  However, air in the line (especially suspect the one that was added) would do what you describe.

I would do a very good bleed and check operation of each piston on both calipers, maybe one is stuck from long time of not moving

[BradT585]

Thanks Chris,
We have thoroughly bled the system and we did get a slight improvement after that but it was still not satisfactory. We did not think to check the operation of each piston, I will give that a try the next time I am at the shop. As for the front/back separation we got hold of a '97 manual and it shows a single line from the hand brake to the right side and a singe line from the rear going to the left caliper, no cross over at all. We are assuming (yeah, I know what they say about when you assume) there is no difference from '97 to '98. We have considered reconnecting the line from the rear but were afraid that would not provide enough fluid pressure to the wheel cylinders on the car axle. Assuming, again, that is why they set it the way they did when they Triked it.
Thanks for the response, please keep them coming. Dad might get it out for a test ride today with just the one caliper configuration, I will give an update. We figure as long as it can lock the front wheel that should be good enough??

[Chrisj CMA]

I wouldnt do anything to degrade the braking power you have at the rear.  With two big ol car tires and good brakes back there he doesnt need the fronts as much as he did when it was a bike, just make sure all the pistons are moving and all the air is out.  sometimes it takes a couple tries.  Also someone suggested (on here) to inject brake fluid through the bleeders as air more easily moves up than down, just remove the master cylinder cover and see if air bubbles are ejected into the reservior?

[PatrickDoss]

Originally, the hand brake operated just the front right caliper, and the foot brake operated the rear caliper and the left front caliper.  The 1800 Wings are the ones that apply pressure to different pistons in the caliper.  All the 1500's work the whole caliper.  The reason behind the original set up is that most people over-brake the rear, especially in a panic stop.  Chris is correct in that it takes more rear brake on a trike than front brake.

On the conversions that separate the front and rear, they usually remove the pedal line to the left caliper, add a brake line to the right caliper with a double-length banjo bolt, and loop the added line up and over to feed the left caliper.  It's very easy for air to get trapped in that added line because of the way it comes up and over.  If that's how your dad's is built, you might try removing it from the left side and lowering the looped portion down to help get the air out.  Then reconnect it to bleed the caliper itself.  As Chris said, as long as there's no air in there, you should have a firm lever.

[X Ring]

Something others have mentioned to get the air out of the system is use something to hold the hand lever down and keep it that way overnight.  That will allow the air to work its way up the lines into the master cylinder.

Marty

[Chrisj CMA]

I talked to an old wing rider....he said a trick they did was:  Dismount the calipers from the wheel to save a bigger mess.  Loosen the hose going into the caliper (essentially creating a leak) and then bleed the lines from that point/taking the calipers out of the equation until you are sure the lines are clear then tighten them back up and bleed the calipers.  I wouldnt have thought that to be helpful, but he said when he had his 1500 he had to do it that way to get ALL the air out.  Just passing it along

[Tx Bohemian]

I haven't had the oppotunity to work on bleeding brakes on a bike but I used to do brakes on cars for a living many years ago.  Here's a suggestion/comment, maybe someone can jump in if this is not related to bikes.

If you replace a mastercylinder on a car it needed to be bench bled before installing it on the vehicle otherwise you'd never get all the air out, and thinking I could save time I tried a couple of times to skip the bench bleeding and install it on the car and attempt to bleed the whole system but always having to remove the cylinder and do the bench bleeding.  My theory on why it wouldn't work on the car is the pedal assembly wouldn't allow the piston to travel completly to "bottom out" in the housing therefore not pushing all the air out.

Seeing as this has been a problem on this trike since new maybe this needs to be done.