Installing new HEL brake hoses and seal kit recommendations

[djsb 491]

I've just received a new hose kit from HELL (sic) with a very confusing packing list and no DETAILED fitting instructions. I also wanted 2 inches longer on the hose from the front brake lever to the ABS modulator (or hose equivalent of a junction box). No indication if this has been lengthened, so I assume not. Does anyone know where the hose from the front brake lever leads to? The actual ABS modulator seems to be under the frunk. There are hard brake lines that lead forwards and backwards from the modulator to some kind of junction where the hard lines connect to the flexible hoses (ABS_SYSTEM_LOCATION.PDF attached). The one for the rear appears to be behind the RH footrest. Not sure exactly where the front junction is. Also, not sure what the black plastic blocks are meant to be for (apart from a possible locking function) on the end of the hoses. They will get in the way when it comes to tightening the bolts. Can they be moved out of the way temporarily and moved back onto the bolts later?

Also, are the brake seal kits for the front and rear master cylinder and calipers on Wemoto OK?

 

Front Master Cylinder

https://www.wemoto.com/bikes/honda/nc_750_xd_dct/14/picture/brake_master_cylinder_repair_kit_-_front_-_trk

 

Rear master Cylinder

 

https://www.wemoto.com/bikes/honda/nc_750_xd_dct/14/picture/brake_master_cylinder_repair_kit_-_rear_-_trk

 

Brake caliper repair kit rear.

 

https://www.wemoto.com/bikes/honda/nc_750_xd_dct/14/picture/brake_caliper_repair_kit_rear_-_by_trk

 

Brake caliper repair kit front

 

https://www.wemoto.com/bikes/honda/nc_750_xd_dct/14/picture/brake_caliper_repair_kit_front_-_by_trk

 

Has anyone fitted these. Does anyone know of any other kits? The official OEM kits are pricey, but maybe worth the extra?

 

I'll have to drain the fluid completely to fit the hoses, and I'm going to be using a manual vacuum pump (a Laser 8018) to remove the fluid. Can this be used to draw the fluid INTO the system as well? I've also bought a Motion Pro master cylinder circlip pliers to remove the circlips from the master cylinders (a replacement for the official Honda snap ring pliers 07914-SA50001) as standard circlip pliers don't reach deeply enough (there are ones for half the price available, but they don't last for long). What silicon grease should I use, and where should I use it? How much DOT4 brake fluid will I need (is 1 litre enough) for a complete fluid replacement? Any decent quality fluid available at a reasonable price? Comma maybe?

Anything else I should watch out for? I'm doing a complete overhaul as the bike has been standing for a few years and I don't want to take any risks with the brakes.

 

 

 

 

 

 

ABS_SYSTEM_LOCATION.pdf

[Slowboy 20,503]

HEL did mine for my SV650 which needed a 2" longer run to the front master cylinder. Was absolutely spot on. Like you said, no instructions, I just removed one at a time and fitted the new one then moved on to the next, working my way from calipers to master cylinder. Make sure you put the same number of seals in as you take out (and in the same place😁) and Bob's you mum's brother.

 

Always been impressed with their quality.

[Andy m 23,543]

The pdf shows a linked brake system. Are you sure yours has that? I thought it was dropped in 2014 because marketing people want you to have brakes suitable for racing on a commuter bike?

 

The pipe from the master cylinder goes into the ABS modulator and comes out going to it's respective calliper. The ports are usually labelled with F/R etc. 

 

On a linked system there is an extra pipe run so part of the rear circuit goes to the extra port on the front calliper. 

 

The "junction boxes" are just where solid pipe turns to hose.

 

I would never drain a system. Just change the hoses and leave anything that doesn't come out alone. You then use the vacuum bleeder to pull out old fluid and air as the new pulls through . Any old fluid that stays behind is in the traps that make a dry system a pig to bleed. Comma is fine, any brand you trust to be the real thing not recycled chinese gravy. A litre will be plenty. 

 

Andy 

Edited May 28, 2022 by Andy m

[djsb 491]

Thanks Andy,

Uploaded the wrong page. It's not a linked system as it only has 1 hose on the front caliper. I'm assuming that the ABS modulator acts to apply or remove pressure on the brake fluid in response to an electrical signal. Where does this electrical signal come from? Is it in the form of a pulsed DC level with a varying pulse width (pulsed width modulation) or some other modulation scheme? Just curious.

[Andy m 23,543]

The ABS sensors at the wheels are just coils. The polewheels induce an AC signal. The electronics are basically analogue at this point. The sine wave is chopped to square then added back onto itself. The variation in the crossing points is directly proportional to the wheels angular deceleration. 

 

The electronics have a set (tuned in by track testing) trigger point where the angular deceleration amounts to deep slip at the wheel . Then it's just a control loop using two solenoids per circuit, apply-hold-release to hold the decel at the point of deep slip where peak braking is. On the track you see it actually find the peak decel and just hold that pressure, but in real life road surfaces vary so it will cycle continuously. It's 20 years since I did development on hydraulic systems, but cycle rate will be 30 to 50 per second, the limit being how fast the solenoids can shift. This barely matters because when you release the pressure the mechanical drag of the wheel spinning up again is slower. This means the typical cycle is apply, apply.... apply, hold, hold, hold..... hold, release, apply, apply... apply, hold..... rather than equal cycles . There is a pump that runs to keep the released fluid at pressure so the pedal doesn't drop. 

 

The technology is 50 years old. They have to keep changing the electronics because you just can't buy old stuff in industrial quantities, but then having fitted the same chip as a PlayStation we programme it to act like something Ferranti made in 1982.

 

Andy 

Edited May 29, 2022 by Andy m