Hi Fellas, Help me with a thought process here before I reach for the spanners. I have an abs bike to which I recently fitted R&G rearsets. These rearsets are not compatible with the brake line microswitch arrangement as used on the oem rearsets; R&G supply a replacement banjo bolt incorporating a pressure switch instead. I have until now left the original banjo bolt in & done without a brake light operated from the rear, but my MOT is nearly due. Knowing that replacing the oem banjo with the pressure switch banjo will introduce some air, I have been reading up on abs bleeding as per proper procedure & think I understand it well enough to have a go. It occurred to me today that if I fit the pressure switch & wire it in instead of the oem microswitch, I may not be able to engage the abs bleed mode; this is normally entered by operating the rear brake lever in a special sequence (amongst other steps). This because I may not have enough pressure in the MC/brake lines to operate the pressure switch, therefor the electrical signals normally sent to the braking ecu by operation of the oem microswitch cannot be sent. Still with me? Do you think think it possible/practical to leave the oem microswitch connected (but tucked away) & connect the pressure switch by splicing onto the respective two wires. The theory being that once bled/functional, the pressure switch will operate the brake light, but for maintenance of the system (if lack of sufficient pressure due to fluid change or part replacement), the microswitch can still be operated by hand to mimic operation of the lever to engage bleed mode. Will the pressure switch happily operate the brake light with the oem microswitch still connected & remaining in the closed position (tucked away until needed). Am I missing something??? I hates abs!!! Thanks fellas.
. Hello mate, Can you not rig the OE micro-switch up by making a bracket for it? That way you can avoid breaking into the ABS circuit. That's what I've thought about doing. I'm assuming btw that the pressure switch you refer to is similar to the one shown at the bottom of this pic: I've got an ABS bike too. I bought this cheapo, surprisingly good quality (IMO), Chinese kit on ebay for it last year but when I opened the box and saw that pressure switch I chucked it up on to a shelf. TBH, I just couldn't face breaking into the ABS circuit on the bike and possibly opening that can of worms. I've since thought again about fitting it and I may have another look at it. I've got a brand new TaylorMade zorst and a PC5 that have been sitting on that same shelf for months too so the original R/H brake/footrest will have to come off when I fit them anyway. As I say I shall be hoping to dodge fitting that pressure switch by making a bracket. Otherwise it'll be going back on that top shelf again. Nick.
Swiss, I wouldn't even think about starting the ABS bleed until you have completed the conventional bleed and have a solid lever/pedal. Once you have a solid lever you will able to activate the pressure switch and activate the ABS bleed procedure. Your idea of having a manual switch for maintenance is genius though
I thought about that Nick but I'm not clever enough to come up with a suitable bracket. I am however more than willing to let you find a solution which I will gladly steal & take credit for.
Slick, Do you think there will be enough pressure in the line & m/c to activate the pressure switch after a conventional bleed? I guess it's worth trying first & still leaves the option to have to switches in parallel. Thanks pal.
Yes deffo you will have pressure once the conventional bleed is complete. Unless you have air in the conventional lines it should not enter the ABS which is why you want to remove air before the ABS procedure. Thinking about it the banjo switch should only need very little pressure to activate anyway.
Swiss, as far as wanting to keep the OEM brake switch for the sole purpose of being able to trigger the abs bleed sequence is not required, all that is required to turn the rear brake light on is to unplug the pressure switch elecrical connector (will also work with OEM switch) and use a piece of wire to bridge across the two wires! that's what the pressure or OEM switches do to turn the light on. As far as the bike requiring a full abs system bleed I don't see this being required as the only air being introduced into the system will be at the rear mc back to the caliper, which as slick mentioned would only require a conventional bleed in order to remove the air from that part of the system. Don't get me wrong you could introduce air into the other parts of the abs systems but it takes quite a bit of time for the fluid to drain when it's only using gravity as its bleed method, as it should only take a minute or so to actually unscrew the OEM banjo bolt then replace with the pressure switch banjo very little fluid will be removed from the system. Also to help limit any fluid draining out and allowin air in I would leave both the reservoir caps on and tight while I was swapping the banjo's and then remove or loosen them to allow the conventional bleed process to be carried out on the rear.
I've been trying (without success I might add) to find some rear sets that avoid having to break open the hydraulics but have drawn a blank so standard they will stay.
. Yes and to minimize fluid loss you could maybe use a clamp on the brake-pipe if it's rubber. Just to clarify; The stop light, as standard, is activated by a micro-switch, right? Just looking at the installation I can't see where the hydraulic switch fits in. I mean, is a hydraulic switch included in the kit because the footrest/brake pedal geometry is so radically changed that it's cheaper than providing a 'custom' bracket?
The OEM brake switch is just a spring loaded switch that makes the "on" connection when the lever is depressed and the spring helps to pull the switch back into the "off" position connection. The switches are two wires which are pretty much joined together when the lever is depressed to sent the power to the brake lights! A hydraulic brake switch makes use of the pressure that builds up in the brake pipes when the lever is depressed to push the connection of the switch to the "on' postion sending the power to the lights via the OEM wiring loom connection. In order to install the switch the banjo bolt that holds the flexi brake pipe into the rear master cylinder is removed and replaced by the new switch to allow it to sense the brake pressure. Below is a pic of a hydraulic switch installed to a rear MC for reference.
Small update on this. I removed the oem banjo & fitted the pressure switch without drama; negligible fluid loss (just the wetted surface on the fittings) & good pressure on the lever straight after without bleeding. No problems activating the switch so no problems entering bleed mode. I still have to bleed the abs unit upstream (under the seat) of the MC (as per the manual) but I also have some speed bleeders to fit so will do it then. So far, so good.
Just to close this out. Pressure switch & speed bleeder type nipples fitted. I had to complete the abs bleed on the rear line, valve unit & power unit, but its actually very easy following the manual; it took about 1 hour really taking my time. Back to hibernation.
