Front Brake Help Needed

[87_442]

Need help figuring out the front brakes on this trike. Front end is from a 2003 Fat Boy, and I'm changing from the stock 10" handlebars to 16" ape hangers. Realized that I would need to get a longer brake line, so I need to fix a locking up issue with the current brake setup while I'm at it. It locks up at low speed, and takes very little pressure to get the wheel to lock up. Don't know how it would work at speed, don't really want to find out.
Would this be an issue with the caliper and pads, or an issue with the master cylinder?

 

[Gorilla]

Jim,

I'm thinking master cylinder first to look at. Check to see if its dirty and needs a system flush. Caliper pistons might also be dirty or rusted not allowing the pistons to move smoothly.
Good Luck

 

[87_442]

Pulled the cap off the master cylinder, and yes, it looks dirty. Master cylinder is at an angle, so naturally the cap came off along with a bunch of fluid. Not a problem, but with the mc angled like that, it will be difficult to fill at that angle. I do have a mighty vac, and can use that. I will be pulling the mc anyway along with the brake line when I change the ape hangers.
What is this in the middle of the cap? A sight glass?



Can you recommend a good procedure to flush and bleed? BTW, this is a single caliper and rotor front brake.

Thanks,

Jim

 

[Gorilla]

To fill you turn the bars all the way to the left that will somewhat level out the MC. To flush open the caliper bleed screw after putting a tight fit hose over the tip. Put the other end of the hose in a jar that has about an inch of fluid in it. Make sure the end of the hose stays down into the fluid in the jar. YOU MUST KEEP THE MC mostly full during this procedure.

Pump the brake handle to force the fluid in the MC and the lines and caliper out the bleed screw thru the hose into the jar. Keep adding fluid to the MC and pump until CLEAN fluid comes out into the jar. Before removing the hose close the bleed screw. Now the system is flushed. Next bleed the system and hopefully that solves your problem. If not plan to rebuild the caliper and maybe the MC. This is a quick instruct. Just to give you an idea of the steps. If you have never done it before keep at until you get clean fluid and no air in the system.

PS. the plastic piece in the center is a sight glass for the fluid level.

 

[87_442]

Thanks so much! I'll see how this goes.

 

[87_442]

16" apes will be in tomorrow. Will be pulling the mc and will need to change the line soon. Rough measurement was between 38-40 inches. Will know for sure when I pull the MC. For rule of thumb, should I go 6" longer on the hose with the longer apes? Know it sounds like dumb question, but...want to be sure.
I can order one through JP Cycles, just need to know size.

 

[87_442]

Have a question about brake fluid. I noticed that the mc cap says to use DOT 5 fluid. I did some reading on the difference between regular DOT4 and DOT 5, and it said that DOT 5 is purple, where this fluid looks like regular brake fluid. Could this have had the wrong fluid in it, and could it have caused problems? It said the two kinds are incompatible.

 

[Gorilla]

Have a question about brake fluid. I noticed that the mc cap says to use DOT 5 fluid. I did some reading on the difference between regular DOT4 and DOT 5, and it said that DOT 5 is purple, where this fluid looks like regular brake fluid. Could this have had the wrong fluid in it, and could it have caused problems? It said the two kinds are incompatible.

Jim yes there is a big difference between DOT 5 and DOT 4. They are NOT compatible. DOT 5 should have a purple tint to it.

Harley for a couple of years went to DOT 5 in their bikes. But then switched back to DOT 4.

IF DOT 4 fluid is put in the system of a DOT 5 the rubber parts will react to it in a different manner.

I would suggest that you look in the manual for the model and year of your bike to see what was put in from the factory.

I would then recommend you flush the system and put the correct fluid in.

If your bike calls for DOT 4 and the MC top says DOT 5 then someone may have changed the top with the wrong one.
Check the rear MC cover also see if it says the same thing.

Its important to have the right fluid because if not the seals in the MC and Calipers will deteriorate causing brake failure.

Either way determine what is supposed to be in there flush and refill with the proper fluid to be safe.

 

[Ayatolla of Rockin' Rolla]

Brethren,
Dot 5 Brake Fluid Is Pure Silicone.

Ayatollah

 

[87_442]

Ok, I don't have an owners manual, since this is a homebuilt with lots of different parts, so all I can go on is what is on the cap. So if this has had DOT4, instead of DOT 5, would it cause the lever to be hard to pull? I noticed when I took the line off when I was moving the MC to the new handlebars that the lever was then easy to move. Second, since they are incompatible, would all the seals be bad?

 

[Gorilla]

If DOT 4 Fluid was installed in a bike that was originally DOT 5 the seals would be softened and start to swell in both the MC and the calipers.

 

[87_442]

Talked to J&P Cycles this afternoon, to get the right length brake hose. I told them about the problem, and they recommended first using Brakeleen to flush out the mc and caliper. They said to install the new hose after and refill it with DOT5 and see how it works. I may have to rebuild both afterwards.
BTW, the mc for the rear is a dune buggy style, with regular DOT4 in it, and what looks like Akebono style calipers installed. Looks like I'll be running two different types of brake fluid in this thing...LOL.

 

[Gorilla]

Talked to J&P Cycles this afternoon, to get the right length brake hose. I told them about the problem, and they recommended first using Brakeleen to flush out the mc and caliper. They said to install the new hose after and refill it with DOT5 and see how it works. I may have to rebuild both afterwards.
BTW, the mc for the rear is a dune buggy style, with regular DOT4 in it, and what looks like Akebono style calipers installed. Looks like I'll be running two different types of brake fluid in this thing...LOL.

Two other options. Rebuild the MC and Caliper for the front with seals etc for a DOT 4 setup. OR replace the MC and Caliper for the front that uses DOT 4. Harley only did the DOT 5 thing for a couple of years. Good Luck. You might get away with the Flush and DOT 5 fill. If the DOT 4 has not done much damage the DOT 5 will be ok. Remember to FLUSH

 

[87_442]

Started the flush on the mc, filling it with brakleen. Question...if you have the line unhooked, and you fill it with a low viscosity fluid like brakleen. shouldn't the fluid shoot out the hole? I'm not getting much out of the mc when I pull the lever.

 

[Sidecarbill]

If this is a home made trike the issue could be there's just not enough weight on the front end. I can easily lock my front wheel at any speed. By the way it won't steer like that. You can argue the dot5 with others here. But I flush the system on any motorcycle I've ever owned and replaced with dot5, no issues. Old dot5 will no longer look purple.

 

[87_442]

The trike is pretty heavy, with the way the frame is built...I hope that it's enough to keep the brakes from locking and the front end down. As for the mc, took it apart tonight...after fighting with the snap ring, got the plunger out...yeah, pretty bad:



If the master cylinder is that bad, the caliper can't be much better. Found a rebuild kit for the 11/16 bore on Amazon...just not sure if it works with DOT5 (would like to stay with that, since they could be from the same bike):

https://www.amazon.com/V-Factor-Cyl...7abfe6&ref_=pd_hp_d_atf_ci_mcx_mr_ca_hp_atf_d

Will have to look for a rebuild kit for the caliper next.

 

[Gorilla]

You will be OK with DOT 5. It will work with either seals. Its when you put DOT 3 or 4 in a unit that has seals for DOT 5. That's when the fluid starts reacting with the seals.

 

[87_442]

Ok, so if I switch the rear master cylinder to dot5, I can just flush the system without changing the seals?

 

[Gorilla]

Ok, so if I switch the rear master cylinder to dot5, I can just flush the system without changing the seals?

Yes you should be able to. The silicone base DOT 5 is gentle on the rubber seals. Its big benefit is it has a higher boiling point which is why its used in racing applications.

 

[87_442]

Ok, that sounds good. Will work on that once this gets fixed.

 

[87_442]

Pulled the front caliper, and tried to find a part number on it...can't find one. All I know is it is a single piston setup...not even sure it is from 2003 or not. Would anybody know where I could get a rebuild kit for this? It seems like it should need one, considering the condition of the master cylinder piston.

 

[87_442]

Went to local cycle shop today with the caliper and mc. Picked up a seal kit for the caliper, which is an older style from 84-99, and ordered the rebuild kit for the mc, which has an 11/16 piston. Good price on the seal kit, $8.99...rebuild for the mc won't be much more. Hope to have this all done next week, then move to the back brakes.

 

[87_442]

Got the front brakes fixed. Master cylinder is rebuilt as well as the caliper. Took it out for a ride, did ok, bled some more air out of the line, and tested it again. Working good now, don't feel any grab to it...you can squeeze the lever pretty good, and it slows it down just enough to make a difference.

Had a couple of nice tests rides on it...it rides good and runs good. Shifter takes a little getting used to, with the slop in it, but it is pretty easy to ride. Hoping to get quite a few more rides in before winter sets in...it's pretty fun to ride!

Going to be installing some new (to me) LED halo ring driving lights this week. Just need to shorten the wires on the pigtail and plug them in with some connectors. Should make a big difference in visibility.

One thing of note...stopped at a neighbors place down the road, who has a tri-glide...he came out of the house and said "What is that?" Told him it was part Harley, on a Honda frame, with a VW engine..he just laughed. I think the reactions of people will be the most fun part!