Marlin 5xi Handbrake Modification
The thread is essentially the fitting of 259mm rear disks with the prime objective to improve the handbrake efficiency of a standard Rover 200/25 doner.
The calliper, carriers and disks were sourced from a MG ZR 160 2001/-, the ones I used were recycled from a scrapyard but new could be purchased if required. New would cost an extra £30 which is the returns set by the re-manufacturers. They will not allow a 200 calliper to be returned in exchange for a 160 calliper.
Disks are Rover/MG ZR 160 259mm with the same offset at the std Rover 200.
The callipers have a 34mm piston the 200/25 used a 28mm piston.
The carriers are the 60mm throw compared to the 200/25 which is 45mm throw.
The pads are approx 20% larger in surface area.
Having set the scene for the new hardware I should also point out that my rear uprights are different to yours, does not matter what you have, mine are custom built and are different. The only difference of interest to this installation is that I have used leading edge braking not the conventional trailing edge braking. The standard 200/25 carriers and callipers fit as normal to the early std upright as supplied by Marlin.
The only other point of interest is the handbrake cable its route to the calliper and the Marlin supplied cable end.
This picture shows the handbrake cable end at the calliper.
The Rover fitment has two bolts holding it in place, the Marlin conversion has only one. It should also be noted that the Marlin cable end/stop, positions the cable out of line with the hasp connection to the handbrake quadrant on the calliper, if you like in both the x and y axis. This could be one component of the efficiency loss for the set up on the 5Exi handbrake. If the cable pulls square on to the quadrant on the calliper and not at a 15 deg angle if may pull up better. However this is not my point the Marlin cable end/stop may mechanically foul the bearing housing of the upright so make sure the stop does not prevent you assembling the set up on the axle.
In my own case I stood off the stop from its mounting to allow for a better alignment but this is not detailed. The fouling of the bearing housing will limit the other axis alignment.
Original set up on my upright.
These shows the 160 calliper set up in place NS and OS you can tell by the location of the suspension spring.
This shows the hasp connection and the general set up.
… and viewed from the top.
The carrier, disk and pads in place showing the pad coverage of the disk.
Its pointless me writing up the step by step assembly, if you competent to be building a kit car you don't need me to tell you how to assemble a set of callipers on a wheel.
All I will say for assistance to the less capable is assemble each component separately, the disk has to be fitted first, the carrier and pads next and then the calliper.
The set up of the auto adjustment i.e. the piston height to suit your pad and disk thickness is technically covered elsewhere on the net I am not repeating it here.
Does it work? Good questions I will add brake efficiency results at some stage, the original set up was tested at 16% the MoT pass is 15% this result is affected by the stated weight of the car being tested.....
When I wheeled the car back into the garage and applied the handbrake it did seem to stop better than before but this is subjective and no judgement of the success of the mod should be implied.
.. and good luck with your changes.
JohnC
spotted points for the picky:-
- the paint will wear off the friction areas on first application of the brakes
- the centre axle nut was mechanically locked after I finished the brake install
- I did not let the red paint dry long enough before assembling, I thought over night would be long enough
- I did release all the air from the system at the end
- I did not apply copper grease to the pictured installation
- Thread-loc will be added to the threads after formal testing
Marlin 5xi Handbrake Modification
Linear Mode
