Unlinked Brakes?

[grumpy]

1995 GL1500 SE with Lehman solid axle conversion. On several occasions we have been on "unstable" road surfaces & needing to brake while going down a steep grade. Invariably, the front wheel locks up before the rear wheels. This is not the scenario I would prefer. In normal riding I use both front & rear brakes together. In this situation I would like to be able to use the rear brakes independently. Therefore I have been considering "unlinking" the brakes. I have read that some trike conversions do this? Does anyone know what is involved? Parts needed? Special tools? A "how to", tutorial, video? Thanks, Stan

 

[rhino65]

1995 GL1500 SE with Lehman solid axle conversion. On several occasions we have been on "unstable" road surfaces & needing to brake while going down a steep grade. Invariably, the front wheel locks up before the rear wheels. This is not the scenario I would prefer. In normal riding I use both front & rear brakes together. In this situation I would like to be able to use the rear brakes independently. Therefore I have been considering "unlinking" the brakes. I have read that some trike conversions do this? Does anyone know what is involved? Parts needed? Special tools? A "how to", tutorial, video? Thanks, Stan

I would be interested in this also for a 02 GW with CSC kit

 

[Marc H]

Brakes are delinked on Champion kits.The install manual is downloadable from their site.I don't think its very hard.

 

[Lee H. Mann]

1995 GL1500 SE with Lehman solid axle conversion. On several occasions we have been on "unstable" road surfaces & needing to brake while going down a steep grade. Invariably, the front wheel locks up before the rear wheels. This is not the scenario I would prefer. In normal riding I use both front & rear brakes together. In this situation I would like to be able to use the rear brakes independently. Therefore I have been considering "unlinking" the brakes. I have read that some trike conversions do this? Does anyone know what is involved? Parts needed? Special tools? A "how to", tutorial, video? Thanks, Stan

Did you ever figure out that brake reservoir problem ?
I take it that the rear brakes are adjusted correctly and you have bled the rear to the front ?

 

[CrystalPistol]

I once considered unlinking my '97 GL1500 / '98 Lehman GTL Trike's brakes, mine has 9" Ford drums. Front just locked too quick in the yard I thought.

Then I jacked her up onto stands and did a proper rear brake adjustment, adjusting up until I heard the shoes scraping the drums .... and no more.

Immediate improvement, much better and no more thought to unlinking my brakes.

Then I added a 10 psi Wilwood Residual Pressure Valve in the rear brake line that holds 10 psi on the seals, etc. Another step in the right direction.

On slick grass, if I stomp on the rear brake alone the front locks first, in gravels .... not so much .... and on pavement, usually one rear will lock first, I've never tried it all out to see if both will .... she stops really fast though as those two 9" rear drums self energize and whoah the rear tires.

I do adjust my rear brakes every spring and anytime later before a longer trip or if anticipating pulling the trailer.

 

[grumpy]

Marc H -- Thanks I will look that up.
Lee H Mann -- No sir, have not needed to add fluid since. Still no evidence of a leak. I am stumped! Yes I have adjusted the brakes with the rear end raised just as CrystalPistol said and replaced the fluid just for giggles.
Crystal pistol -- The rear brakes (9" Ford) work very well, stop the unit just fine, it's just that on gravel roads or wet/slick/sand/mud/snow going down hill if I have to brake (I try to be geared down before I get to these kind of things, but sometimes they sneak up on me) the front wheel locks up & I have to just let gravity do it's thing and I don't like the feeling at all! I will consider the residual valve. Where in the line did you put it? IIRC when I added one to my 99 Valk trike it went right after the steel line that crossed over to the left side.

 

[CrystalPistol]

Grassy areas are about the slickest stuff I have reason to ride on. Seldom mud, snow once, and never a problem on gravel roads that I've been on.

Here's a repeat with picture from another thread.

I plumbed a residual pressure valve into the rear lines of my Lehman trike a whole lot cheaper than that. I used a Wilwood (https://www.summitracing.com/search/product-line/wilwood-residual-pressure-valves) valve I picked up at Summit Racing. You'll see two without adapters, 2 with adapters. I bought the 10 psi one with adapters.

Use 2 psi for disc brakes .... 10 psi for drum brakes (which have return springs).What they do is keep that amount of pressure on the system between them and the calipers or wheel cylinders. Keeps seals and such under slight pressure.

I used a 10 psi version as I have drum brakes and it reduced rear brake pedal travel a bit.

As I recall, the Honda lines were Metric Bubble Flare and the adapters to the Wilwood unit are regular SAE 10mm double flares. I used a longer line with the correct bubble flares and made two shorter lines by adding two SAE fittings and double flaring with a Cal Van 161 inline tool.

After I was done, I cleaned everything and coated with a good clear coat.

Make sure the lines are placed so they DO NOT get caught between the axle or swing arm and trike frame.
View attachment 42579

 

[Marc H]

There are screw in adapters available at your auto parts store to go from bubble to inverted flare so you don't have to cut and splice anything.

 

[CrystalPistol]

Well, that is a way to do it. Did you notice much of a change in front brake lever travel afterwards?????



This sounded so easy when I read it ....

 

[GoldWingrGreg]

I can't speak for the OP, or for that matter about GL1500s, but on GL1800s that use the front lever for front brakes and rear lever for rear brakes, there is a noticeable difference in the front lever pull. Basically, the lever has to be pulled on harder. It's because the master cylinder (m/c) is designed to push fluid volume to 3 caliper pucks, and once de-linked the m/c then has to push fluid volume for 4 pucks. For proper braking with 4 pucks, a larger inside diameter bore in the m/c is needed. Usually trike kits that de-link the brakes come with a braided brake line going to the ADV that somewhat helps, but not so much. I don't ever recall being able to lock up a front tire on a trike with de-linked brakes.

 

[grumpy]

Yes, the travel is a bit more. But only a little. The braking is very solid, but I might still have some air trapped in there. The hose from the right caliper to the left runs up over the fender & then down, so could be air at the top. I will be removing the front wheel in a few days to replace a broken fender guard & I will re-bleed the brakes while I am at it.

 

[grumpy]

Don't do it!!!

DON'T DO THE MOD THE WAY I DID! I found that this degraded the rear brakes. Immediately after completion the braking seemed fine, but after about 150 miles of riding the brake pedal got extremely "hard" at the end of it's travel and the rear brakes were not doing much stopping. I can lock up the rears, but I literally have to stand on the brake pedal to do so. This is an unsafe situation. My theory is that the brake fluid in the line from rear to front is being compressed to it's maximum before the rear wheel cylinders can fully apply the rear brakes, causing the brake pedal to stop its travel before full rear braking can be achieved. Until I can find a solution to this, no one should do this in the manner I described. Also, how do I go about having my post (#9) removed from this thread?

 

[Gorilla]

DON'T DO THE MOD THE WAY I DID! I found that this degraded the rear brakes. Immediately after completion the braking seemed fine, but after about 150 miles of riding the brake pedal got extremely "hard" at the end of it's travel and the rear brakes were not doing much stopping. I can lock up the rears, but I literally have to stand on the brake pedal to do so. This is an unsafe situation. My theory is that the brake fluid in the line from rear to front is being compressed to it's maximum before the rear wheel cylinders can fully apply the rear brakes, causing the brake pedal to stop its travel before full rear braking can be achieved. Until I can find a solution to this, no one should do this in the manner I described. Also, how do I go about having my post (#9) removed from this thread?

Done

 

[CrystalPistol]

DON'T DO THE MOD THE WAY I DID! I found that this degraded the rear brakes. ... etc ...

Thank you Sir!

Looking at some manuals, I see Champion had the line to front brake removed from rear MC side port and the line to rear brakes moved over to that position and a plug was put in the end port originally used for rear brakes. They also used a simple crossover line up front with longer banjo bolt and new washers.

 

[grumpy]

Thank you Mr. Gorilla, sir. I really hate to put out bad/misleading info.

 

[Red Wing One]

I can't speak for the OP, or for that matter about GL1500s, but on GL1800s that use the front lever for front brakes and rear lever for rear brakes, there is a noticeable difference in the front lever pull. Basically, the lever has to be pulled on harder. It's because the master cylinder (m/c) is designed to push fluid volume to 3 caliper pucks, and once de-linked the m/c then has to push fluid volume for 4 pucks. For proper braking with 4 pucks, a larger inside diameter bore in the m/c is needed. Usually trike kits that de-link the brakes come with a braided brake line going to the ADV that somewhat helps, but not so much. I don't ever recall being able to lock up a front tire on a trike with de-linked brakes.

I de-linked the brakes on my 2013 Lehman (2012 GL1800) using the Champion instructions.

I agree that when you follow the instructions, you end up with four pistons when applying the front brakes. What you say about needing a larger piston in the MC to drive the four pistons is wrong. Simple hydraulics tell you that if you increase piston bore in the MC, you decrease pressure output which makes it harder to push the brake pistons.

If you want to increase pressure you need a MC with a smaller piston.

My front brakes work very well with four pistons.

De-linking improved the rear brakes, but they were still not great.

I then improved the rear brakes by lengthening the brake pedal approx 3inches (more leverage )I was able to do that because I have the RS Comfort Controls......What I did was eliminate the linkage and welded an extension into the pedal.

 

[CrystalPistol]

Well, it's coming up on fall & then winter and I'm thinking of all new SS braided soft lines for the '97 trike as every line on it is OEM still. They are in good shape though. At the rear, the conversion reused the hard line formerly attached to the rear caliper, only now it goes to a tee. I think there is just one short section of soft line in the rear from rear MC over to swing arm.

I'm just debating now, do I want to delink the brakes or leave as is. I know that if I delink, I would operate both front calipers off the one handlebar MC, travel would increase some … and I know of two methods. Either a single double banjo at the MC and two long lines, or a double banjo at one caliper and a line running over to the other. If I did this, I would leave the old line from rear MC to left front largely intact (ain't like it's heavy), just flush and cap it and stow away or remove / cut / plug unused left rubber hose. I'd maybe use a 2 or 3 psi RPV in front. I have a 10 PSI RPV in back line already there just before the tee on the axle which has steel lines to rear wheel cylinders (new).

With linked brakes, I noticed at last look, the left rotor and pads wear faster than the right front. Still serviceable, but …

Just thinking. Saw link in my notes, reviewed what others have done.

 

[Lee H. Mann]

Myself, I would keep the linked brakes on the trike since it acts more like an automobile once trike-d than it does a two-wheeler.

You get more braking with linked brakes.

In a crucial stopping situation, you are less likely to lock up the rear brakes when they are linked.

JMHO:cxtv:

 

[CrystalPistol]

I know "me" pretty well. If I delinked the brakes while installing the SS braided lines, I'll always wonder "if" that alone is enough to give me pause. I'll about 99.44% for sure go the route of leaving them linked … and see the difference with SS braided lines with no other changes first in any event. Besides … it's not that I'm unhappy as is, I've had some critical stops, and it does do it well. When I put the Avon Cobra on front just a couple thousand miles ago at most, I noted the heavier rotor wear on the left. I know why too. I had forgotten that I swapped the rotors (checked runout too, found my notation in maint. records) so now the least worn is on the left, and operating great. I put new pads on then too.

I do like the idea of multi piston front calipers with XX % of piston area operated by rear MC and then the balance % operated by the front MC on handle bar (the load and wear on front left & right brakes would be shared) … instead of left vs right, but that's how it is with the "pre 1800" GLs.

Myself, I would keep the linked brakes on the trike since it acts more like an automobile once trike-d than it does a two-wheeler. Yes

You get more braking with linked brakes. I guess it depends on technique, but for sure one would need to change habits.

In a crucial stopping situation, you are less likely to lock up the rear brakes when they are linked. I thought about that, especially on a damp road. Those drums do work well.

JMHO:cxtv:

Oh well, maybe I just have too much time on my hands … and think too much? It was late, NOIR was slow on TCM, Wife was reading, I was maybe bored too.