Main Menu

hydraulics

A long time ago I mentioned that I had used pieces of wooden dowel inside of the suspension cylinders to prop the DS suspension up in order to keep the car at ride height without hydraulic pressure.
Here is one of the front dowels, now nicely soaked in LHM after years in a cylinder!
The dimensions are 95mm x 23mm. I used wooden rod - you could use anything strong enough but the wood is soft enough to prevent any damage. You should probably use old spheres when doing this to prevent damage to the dampers in the sphere entrance.
I dont have access to a rear dowel at present but I know that the width is the same as I used the same wood...

Nothing to report, just a nice photo of the brake and accelerator pedals on a DS.

16-01-2005 Finished re-piping the rear hydraulics today. After fitting all of the newly made hydraulic pipes I checked the nut on each one to ensure it was tight and applied a blob of yellow paint to each one to show that it had been checked.

Not much been happening with the DS lately, mainly because I've spent the past 3 months entertaining our companys Indian team!

Well since it's the last day of the year I decided I'd better get some work done, especially if I want to get this car ready soon (which I do...). I'd stripped the rear brakes earlier in the year, including removing all of the hydraulic pipework. I'm busy making up new hydraulic pipes but I did manage to rebuild the mechanical elements of the brakes.

The brake shoes were in good condition so I left them alone, but the adjustment mechanisms were not. The rear brakes on the later DS have two means of adjustment; one is by means of snail shaped cams which move the shoes in and out, the other is by eccentric cams acting on the bottom of each brake shoe. The snail shaped cams on my car were completely seized up so I spent hours with penetrating oil freeing them off, they are moved using a 14mm bolt on the back of the brake unit. They still aren't 100% but at least they can now be adjusted! I considered removing them from the car however a special tool is required to re-rivet them in place and since I didn't have this tool I decided not to risk damaging them.

I removed all of the parts of the rear brakes (other than the snails) and cleaned them up. After a lick of black paint the rebuilt wheel cylinders were then fitted along with a new hydraulic pipe, and new seal of course. I then rebuilt the brakes using copper grease on all moving parts. I used some light machine oil on the cams so hopefully this will soak in over time.

Adjusting the rear brakes requires the use of a special tool, which is basically a guage to determine the clearance of the shoes from the brake drum. You can make this guage out of an old brake drum and I used to have such a tool, but typically today I couldn't find it! I've therefore roughly adjusted the brakes by feel and I'll properly adjust them when the tool turns up. Not a very exciting photo, but there was lots of work to do here!!

With both ends flared you can shape your new pipe carefully, avoiding sharp kinks. Once you have the perfect shape place a new seal on each end of the pipe and it is ready for fitting to the car.

Here you can see the new flare formed inthe end of the pipe.

Put the top half of the tool in place and bolt it down, making sure that the former does not get cross threaded. It should be bolted together fairly tight so that the pipe cannot slip whilst it is being flared.
Using a 19mm socket or spanner slowly tighten the former as shown until a positive resistance is felt and the screw will not turn any further with moderate pressure. Never use force with this tool.
When this stage is reached unscrew the former and then unbolt the tool halves and remove the pipe.

After 4 years of restoring I finally took the plunge and bought a pipe flaring tool! This tool creates the little bulges in the end of hydraulic pipes; note that Citroen flares are different to normal brake pipe flares so you need the special Citroen tool. I bought mine from Pleiades, it is relatively expensive but invaluable if you own a few Citroens.

Here's how you use it.

Cut your pipe to length using a hacksaw. Pipe-cutters aren't recommended.
Use a file to level and smooth the ends of the pipe, then blow the pipe through with compressed air to get rid of swarf.
Make sure the pipe is perfectly straight and then put the pipe nut on. (It's incredibly annoying if you forget to put the nut on first!)
Place the end of the pipe in the bottom half of the tool so that the end lines up with the line scribed into the tool and then place the bolt in the tool, so that the end of the pipe enters the end of the former as shown. Make sure that the two anti-rotating bars are in the slot cut into the tool.

I cleaned and resprayed the body in green and re-assembled the cylinder using LHM as a lubricant. I've labelled this up as having some wear and put it back in my stock as a spare.

Incidentally those white marks on the dust seals mean that these seals are suitable for either LHM or LHS fluid. Parts suitable for LHM only have green markings and those for LHS are marked red.

You can't make it out too easily in this picture but there was substantial wear on the pistons and therefore the bores. Presumeably the pistons had been sticking at some point. This means this cylinder is no use for my car, but I'll rebuild it anyway as am emergency spare. The o-rings around the middle of the pistons should be replaced.

To dismantle these late cylinders you simply pull the pistons out, there are no circlips holding them together. Here you can see the two pistons removed from the body with the dust seals attached to them. I've also removed the bleed nipple.

I had this spare rear wheel cylinder in my stock so I thought I'd dismantle it and rebuild it for use on my car.

Even though I'd already sprayed the LHM reservoir, I wasn't happy with the waulity of its finish, so I did it again!

When painting small items such as this the steps I take are as follows:

Sand / wire brush old paint back, usually to bare metal
Prime using either zinc rich or etch primer. You can get away with not etch priming, but you need to check that the paint is sticking properly by sanding it back once it's dry.
Flat the primer back with 400 grit paper
Apply a number of coats of colour, then leave to dry.
Apply 3 to 4 coats of clear laquer and leave to dry over night
Apply a good few coats of wax polish

This gives a very tough shiny finish.

A number of items on older Citroens are painted in brown, a colour not listed in any of the manuals. I got a close match using Rover Clove Brown, you can see I've repainted the straps on this reservoir using it. I just need to find some new bolts for the strapping and stick that LHM sticker down now. The LHM drain pipe was refitted using new Ligarex strapping.

My old steering rack was beyond repair, so I ordered a new one from Pleaides. This didn't come with the track rods however, so I painted these to match the new rack.

I also inspected the balljoints; they were in good oncdition and just need cleaning and re-greasing.

The pressure regulator is now fully relocated. Whilst I was plumbing this in I took the oportunity to degrease the gearbox housing, which was very dirty indeed! I also dismantled, cleaned and greased the gearchange linkage at this point.

I made a new output line from the relocated pressure regulator with a coil in it to absorb vibration. This line was wrapped in rubber to stop it rubbing on any engine components when the engine is running.

In order to reduce the noise of the regulator, I put neoprene foam between the regulator bracket and the new mounting plate. The sphere attached here is an old one, just to test the weight.

I decided to relocate the pressure regulator, to make it easier to get at. I made up a supporting plate, which is basically a T shaped peice of metal, folded in two, with some bracing traingles welded into it. This was then bolted and rivited to existing holes in the front chassis arms. The regulator, and it's original braket were then bolted onto this. I plan on having a flexable HP line made up, to connect to the HP pump; this will eliminate the risk of the line shearing, as the pump is attached to the vibrating engine.

This picture shows the correct type of suspension sphere for the Deese, which is screwed together in the center, rather than being a solid welded unit. You can also see the 'extender' screwed into the suspension cylinder, which must be used to clear other engine parts. I got a full set of these spheres secondhand, and plan on having them professionally rebuilt.

This is the finished regulator, complete with yellow paint marking the important fixings, as originally applied by the factory.

Here I'm busy re-painting the regulator.

This is the pressure regulator and accumulator sphere, just after I removed them. I plan on re-locating the regulator, perhaps on the gearbox, or on the caisson - I'll photograph this as I do it.