Platinum Member V Posted January 19, 2022 Platinum Member Share Posted January 19, 2022 My 1993 XJ had the factory fitted ABS removed 20 years ago. I modified the OEM brake balance valve back then to work with the new ZJ rear disc brakes. This has been fine for decades but the balance valve has failed and I have treated my 29 year old brake components to a refresh. Sadly, original parts are no longer available new. So I upgraded my 1993 to 2001 non-ABS XJ specification instead to match my other XJ. I chose not to use the TJ Rubicon balance valve this time and bought a Wilwood adjustable valve. This greatly improves the safety of the brakes by giving the Jeep an extra fail safe of a split front circuit. The OEM balance valve was both front brakes on the same front circuit. The Wilwood also enables me to precisely adjust my rear brake hydraulics so I get maximum braking without locking up the rear tyres. MoT rollers are useful for this. My problem is that I'm not sure if my Jeep has to have a low pressure warning lamp for the brake hydraulics. The OEM balance valve had a pressure differential switch, my Wilwood doesn't. I can make an electronic circuit that does the lamp test and uses three pressure switches, one in each circuit to monitor the pressure, but I would rather not have make this before the MoT next week. I found this MoT guidance note, but the second paragraph of 1.1.4 has got me confused. What does it mean? Quote Link to comment Share on other sites More sharing options...
Platinum Member V Posted January 20, 2022 Author Platinum Member Share Posted January 20, 2022 (edited) I had an idea that may just need a relay or a latching relay to add to the circuit between the brake pedal switch, the Wilwood pressure switch and the instrument cluster. I need to poke around with a multimeter in the loom plug for the OEM balance valve to see what the signal states are. Edited January 20, 2022 by V Quote Link to comment Share on other sites More sharing options...
Ludders Posted January 20, 2022 Share Posted January 20, 2022 (edited) You don't need worry unless the ULW (un laden weight) of your vehicle is over 3050kg and fitted with air brakes: Quote A vehicle with an ULW up to and including 3,050kg with a reservoir coupled direct to the induction manifold or a reservoir integral in a servo unit, is not necessarily required to be fitted with a warning device. This is aimed at Light Goods Vehicles. Edited January 20, 2022 by Ludders 1 Quote Link to comment Share on other sites More sharing options...
Platinum Member frosty Posted January 20, 2022 Platinum Member Share Posted January 20, 2022 i think that the low pressure warning part ( 1.1.4)is for vehicles with full hydraulic power brakes, such as Citroen's used to have, where you had a warning lamp of low hydraulic pressure at the accumulator. Quote Link to comment Share on other sites More sharing options...
Platinum Member V Posted January 20, 2022 Author Platinum Member Share Posted January 20, 2022 Thanks. That's great news. I finished the plumbing for the master cylinder this evening and I was worried I would have to fit an OEM balance valve. 1 Quote Link to comment Share on other sites More sharing options...
Platinum Member frosty Posted January 21, 2022 Platinum Member Share Posted January 21, 2022 no problem Vince, good luck with the MOT, i can understand your concern on a MOT for a heavily modified truck, but i am sure you have a understanding tester, which are getting harder to find these crazy days. 1 Quote Link to comment Share on other sites More sharing options...
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