Lehman gtl 1500 problem brake rear

andrea74 · Apr 12, 2023

hi, sorry for my english but i use the translator: i have a problem with my gl 1500 trike, the rear brakes are not very effective despite having changed everything including the original honda master cylinder new brake shoes - cylinders - aeronautical hoses properly purged but the pedal remains a bit long could you help me? is there any changes?

andrea74 · Apr 12, 2023

valvoline red

what are these valves for? do they increase the pressure in the system?

Jack Klarich · Apr 12, 2023

andrea74 said:
what are these valves for? do they increase the pressure in the system?

Residual check valve keeps slight pressure ready for the rear brakes, it helps the pedal pressure and stroke, if you do not have one get one

CrystalPistol · Apr 12, 2023

I used a Wilwood residual check valve on my '97 GL1500 / Lehman GTL / trike drum rear brakes, in line, immediately in front of the tee. Drum brakes have return springs, so you can use the 10 psi one, it just keeps 10 psi on the seals, etc. That and regular adjustments so I could just hear a light scrapeing as the wheel was turned by hand, no brakes applied ....worked well for me. I did make my short adapter line.

CrystalPistol · Apr 12, 2023

andrea74 said:
what are these valves for? do they increase the pressure in the system?

No increase, they just shut at a designated pressure to keep some little residual pressure behind them, like to keep seals full, etc.

Jack Klarich · Apr 12, 2023

andrea74 said:
what are these valves for? do they increase the pressure in the system?

No increase, they hold residual pressure @ the wheel cylinders , this gives you a firmer pedal as the wheel cylinders are always ready so to speak

[FONT=&quot]residual valve is used to [/FONT][FONT=&quot]hold pressure against the springs in the drum[/FONT][FONT=&quot]. This allows the drum brake to engage more quickly and reduces pedal trave[/FONT]

andrea74 · Apr 17, 2023

valve parts link

hi, could you tell me where I can buy the valve and all the necessary fittings in Italy, I have some problems finding them....How to properly bleed the brakes: first the rear then the front? in the future with this valve does not change anything ? at the level of purge I mean

Jack Klarich · Apr 17, 2023

andrea74 said:
hi, could you tell me where I can buy the valve and all the necessary fittings in Italy, I have some problems finding them....How to properly bleed the brakes: first the rear then the front? in the future with this valve does not change anything ? at the level of purge I mean

You could check a speed shop or high performance shop for the valve, start in the rear when bleeding unless your trike has linked brakes, check to see if you can find an adjustable valve, that will give you more control on your braking

andrea74 · Apr 18, 2023

new master pedal but long stroke

nothing done tried to bleed there is no air in the system but the pedal feels rubbery with a long stroke .now I buy the 10psi valve..how do you adjust the brakes? do they just have to be in contact with the brake drum or does one have to come before the other do you have any pointers? It could be that having the parking brake kit there is more resistance

Jack Klarich · Apr 18, 2023

andrea74 said:
nothing done tried to bleed there is no air in the system but the pedal feels rubbery with a long stroke .now I buy the 10psi valve..how do you adjust the brakes? do they just have to be in contact with the brake drum or does one have to come before the other do you have any pointers? It could be that having the parking brake kit there is more resistance

Feel for a lip on the brake drum first, sand the drum

Click the star wheel adjuster @ the bottom of the shoes, (down stroke on the wheel) to spread the shoes, keep trying the brake drum on while feeling for some resistance, not too tight or the drum will not turn. That is your initial setting for the brake shoes

andrea74 · May 2, 2023

rear psi lehman gtl 1500

I've seen it written that 60% goes to front brake while 40% goes to rear, but I don't know it to be so. Motor Trike says to swap them in a trike, or they once did, to increase rear braking on pedal.? correct?

rhino 2 · May 2, 2023

andrea74 said:
I've seen it written that 60% goes to front brake while 40% goes to rear, but I don't know it to be so. Motor Trike says to swap them in a trike, or they once did, to increase rear braking on pedal.? correct?

The front brakes by design, either be it on a car / truck or motorcycle deliver most of the breaking power at the front wheel/wheels…

andrea74 · May 3, 2023

CrystalPistol said:
I used a Wilwood residual check valve on my '97 GL1500 / Lehman GTL / trike drum rear brakes, in line, immediately in front of the tee. Drum brakes have return springs, so you can use the 10 psi one, it just keeps 10 psi on the seals, etc. That and regular adjustments so I could just hear a light scrapeing as the wheel was turned by hand, no brakes applied ....worked well for me. I did make my short adapter line.

I've seen it written that 60% goes to front brake while 40% goes to rear, but I don't know it to be so. Motor Trike says to swap them in a trike, or they once did, to increase rear braking on pedal.? correct?

rhino 2 · May 3, 2023

andrea74 said:
I've seen it written that 60% goes to front brake while 40% goes to rear, but I don't know it to be so. Motor Trike says to swap them in a trike, or they once did, to increase rear braking on pedal.? correct?

In a hard braking situation....The weight if the bike will shift forward which in turn take the weight off the rear wheels and if too much power gos to the rear they will lock up and be like skis...And on a two wheeler can cause a low side..Crash ....

So 60% F 40% R is correct...

CrystalPistol · May 12, 2023

Even after a good initial adjustment where you hear the drums gently rubbing the shoes but can still turn by hand ... you will periodically need to adjust the rear brakes up as the self adjusters only work when stopping sudden or with a load after backing up. They do not work going forwards. They need force encountered in backing up.

I have a slight upgrade driveway, I often let the trike roll rearwards and then stomp hard on the rear brake.

rhino 2 said:
In a hard braking situation....The weight if the bike will shift forward which in turn take the weight off the rear wheels and if too much power gos to the rear they will lock up and be like skis...And on a two wheeler can cause a low side..Crash ....

So 60% F 40% R is correct...

That makes perfect sense for a 2 wheeler or a car with 4 wheels, but these trikes have a 3" wide single front tire print and two rear heavy tires (7 to 9" print each) with a heavy rear axle, the rear tires are like flywheels too at speed. They are easily over half a trike's braking force.

rhino 2 · May 12, 2023

CrystalPistol said:
I have a slight upgrade driveway, I often let the trike roll rearwards and then stomp hard on the rear brake. That makes perfect sense for a 2 wheeler or a car with 4 wheels, but these trikes have a 3" wide single front tire print and two rear heavy tires (7 to 9" print each) with a heavy rear axle, the rear tires are like flywheels too at speed. They are easily over half a trike's braking force.

You can’t override Newtons law when going forward and braking hard the weight of the rear will be transferred forward and so too much hydraulic power from the brakes (with the now lifted/lighten rear end) going to the rear brakes will lock the tires. That’s why most trikes have proportional brakes and in the near future they will all be required by law to have antilock brakes, Which will stop the tires from locking …

CrystalPistol · May 12, 2023

rhino 2 said:
You can’t override Newtons law when going forward and braking hard the weight of the rear will be transferred forward and so too much hydraulic power from the brakes (with the now lifted/lighten rear end) going to the rear brakes will lock the tires. That’s why most trikes have proportional brakes and in the near future they will all be required by law to have antilock brakes, Which will stop the tires from locking …

Not questioning Newton. Look at all the added steel rear frame work, 6.75" Ford rear axle, two 9" brake drums, two 15" rear wheels with a 28 pound tire on each (spinning at speed too), and a longer exhaust, often a hitch too, fenders of a wider body ... and ask yourself if the GTL trike is balanced as it was when it was a bike. All that added weight is very low too, not easily shifted under braking as a load of people in a car. Under maximum braking, a GTL trike will greatly compress the forks, lock the front tire even, but the rear is not lifted.

As a bike setting on a center stand, the GL1500 has the rear tire airborn. As a GTL trike, if the center stand is still in place and used, the front wheel is free of the earth contact. It's both a huge weight increase and a huge center of mass shift to the rear that are created with a trike kit. No body wants the rear brakes locking I hope, but on these trikes, rear braking is vital.

Lehman gtl 1500 problem brake rear

andrea74

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