Repair and maintenance of the hydraulics.
The dot is best changed every 2 years.
when the brakes are off the calipers are open to the dot tank via the dump lines or return lines. So opening a caliper nipple will drain the dot. Then fill up with new dot snd when new dot runs from nipple lock up job done. I recommend that every 6 years the top of the tank is removed and the tank cleaned with Dot 3 or 4.
What goes wrong.
The brakes drag. This is caused by flexible hoses collapsing inside and acting like one way valves. Easy to replace and the hoses are the same as any Brit car. 3/8 unf. Or the master cylinder Shad 1 only, is incorrectly adjusted.
No reserve capacity and the lights come on when the brakes are applied. The accumulators have lost the nitrogen charge £120 each. The car is dangerous to drive because if the engine stalls no brakes.
The metal pipes do rust and I use kunifer to replace.
These are the faults that I often come across. Once fixed the system starts to work properly.
The wheel end is the same as any car. Which means pads and disk replacement when needed.
The pumps these run off the camshaft and sit in the valley of the engine. They are plunger pumps. There are no seals, the clearance between plunger and bore is less than a Dot molecule.
The brake valves are the same.
The other valves can be overhauled with o ring kits which are not expensive.
There are no plastic clips on a shadow everything is bolted together and can be dismantled. Even electrical switches for the warning lights. The only special tool is a zero to 3000psi gauge which is about £10.
The accumulators require at least 350ft lbs to split with a special spanner. Reports of 1100 ftlbs have been noted to release the locking ring. Also the spheres must be sealed properly because also reports of sphere lasting less than a year. For these reasons I brought 2 teconditioned ones for Rolls Royce. These are now 19 years old and still have a good charge of nitrogen 90 pumps to lights on. They cost £70 each then.
Also a fitter while working with a nitrogen accumulator on a digger made a mistake and the sphere voilently split taking his fingers with it. So don't mess with spheres.
The spheres can be recharged with nitrogen £20 each. However if the diaphragm has been forced agianst the nitrogen charge valve due to no nitrogen then most likely the diaphragm will split. Because mine have been rebuilt by Royce I will get away with a recharge when needed providing I dont allow them to get to low. 20 pumps is the minimum before recharging. Citroën guys can do this. Or aeroplane lads.
So in conclusion the system is simple and within the scope of diy.
Note. Lucas Girling Castrol red rubber grease. This is dot compatible. I use it to assemble calipers.
When I worked for plod our BMW bikes used to seize the caliper pistons. One by one we stripped the calipers and reassembled using rubber grease no more seized calipers.
I pack it under the dust cover pf calipers to keep damp out of the gap above the caliper seal. I font get seized calipers
Regards
Bob Reddington.