Parking Brake Pedal

This one had me scratching my head for a while.......

The parking brake on my DS21

The parking brake on my DS is foot-operated and, over the years, the mechanism had begun to look a bit tired and was gummed up with grease and dust.

The parking brake was looking tired

The pedal unit had been removed from the cabin a long time ago - mainly so that the engine bay area was free of the cable -  however it wasn't until late 2022 that I turned my attention back to it. The rust was only on the the edges and part of the surface, surface and all it really needed was a refresh.

It just needed a re-spray. However it's made of several moving parts - so how to do that?

My 'tired' brake unit having a lie down......

'Citrothello' carries out comprehensive dismantling and reassembly. You can find that on his website HERE. He dismantles the units and re-plates some parts to make them shiny again.

'Citrothello' carries out a thorough restoration to 'as new' finish

Parts are removed for zinc plating

However the unit is rivetted together, and while dismantling held no fears for me, I did regard it as 'destructive'. I thought about reassembling with some clever two-part 'binding screws'.......

I considered binding screws to replace the rivets

.....but - as with the spirit of the whole restoration - decided to dismantle as little as possible. All I wanted to do was to give it a quick tidy up and some fresh paint.

 

Removing the large split pin and bushes that holds the brake cable was straightforward. I had already ordered a new replacement pin from Dirk Sassens earlier in the year (his part number 8169)

A split pin holds the parking brake cable

Removing the split pin.......

.....allows the cable to be withdrawn.

The parking brake is operated by a foot pedal and then locked in the 'on' position using a lever. That lever has it's own locking knob (and and also a litle rubber-tipped locking knib!). The knob is pulled against the resistance of a spring and locked into place in a plastic 'gate' to hold the hand brake on or off. The small knib inside the gate locks the knob into position to prevent it accidentally being released.

The locking knob......

.....is 'spring loaded' against the plastic gate.

To paint the metal body up, I would need to remove the plastic gate and knib. The platic gate is simply held on by a few screws. But first I would need to remove the plastic knob.

 

And that's where my problems and delays began......I couldn't work out how to remove it!  My car is a 1968 model and the design of the locking knob is ornate - reflecting the design of the knobs on the dashboard - and is specific to the 1968 year.

The design of the knob matches the dashboard buttons

The parts book shows the 1968 and post-68 designs and shows a hole where a pin or rivet would hold the knob on. Parts 10 (ringed) and 13 were for the 1968 model year only. After that, part 10 (not ringed) and 14 were fitted.

Parts book extract showing a pin hole for a fixing

I tried to understand how the mechanism might work: from the parts it looked as though the rod (part 18) was inserted through the knob (part 10) slightly compressing spring (part 18) as it did so. Part 18 was then held in place in the locking arm with a pin through it and the locking arm at point '?' - keeping the spring inside compressed. A cap (part 13 or 14) covered the hole in the knob where part 18 passed through.... I reasoned that knob 10 could be pulled - compressing the spring further - but because part 18 was (split) pinned in place, the spring would cause the knob to spring back once you let go.

 

The problem was that there was no hole on my locking arm? There were marks that looked a bit like a closed up hole (where a pin or rivet might be/ might have been) but  - from studying photos of other knobs - it didn't seem to be quite where I expected a hole and pin to be. And they were off-centre.

Despite what you might think you see - no signs of a pin hole. Or rivet...

I started playing detective: part 11 (a spring) and part 18 (an inner shaft) were common to both years. You can clearly see the pin hole in part 18 and where it fits inside the arm (shown as '?'). There is no part or part number for any kind of pin or rivet. The length of part 18 changed for the 1968 model year - meaning any pin hole though it may correspond to a different '?' spot on the arm.

I asked far and wide and sought out other photos - especially from other people that I knew had 1968 cars. I raised questions on 'Aussiefrogs' - the Australian Citroen forum.....

 

Arrow shows a split pin (photo credit: Faulksy)

Split pin hole (photo credit: Faulksy)

As they both have LHD 1968 cars like mine, I asked Graham Hersey in the UK and and Stefano Orio in Italy. They were very helpful but I almost wish I hadn't asked - as I got mixed and confusing answers: one 1968 car had a pin through the brake arm, the other did not!

Same knob, no split pin (photo credt: Graham Hersey)

Same knob - but a split pin!! (photo: Stefano Orio)

I was getting nowhere and still couldn't remove the knob. While I sought advice, I cleaned up the old brake mechanism, but couldn't do much more. With the knob and knib still attached, there was only so much cleaning I could do.

Weld marks on the arm

I recall seeing that one of the European suppliers - Dirk Sassens -  sold secondhand knobs off the brakes. How did they get them off? And how is a buyer meant to fit them? I sent an email asking these questions. Using Google translate it went like this.....

 

Hallo Uwe

Kann ich bitte technische DS-Beratung haben? Weißt du bitte, wie man diese spezielle Art von Pallas-Knopf entfernt? (Pallas betatigungsknopf 1965-1968). Steckt irgendwo ein Stift durch die Welle? Oder versteckt sich hinter dem Chromeinsatz eine Schraube und Mutter für die Feststellbremse? (Ihre Teilenummer 6734). Vielleicht weiß jemand bei Sassen wie?

Vielen Dank

Paul

 

To my surprise - I got a phonecall back from Germany! I was really grateful that Sassens had  bothered to call me - but they couldn't really help. I was told that there should be a split pin hidden away there somewhere......

Citrothello's website includes some handy photos on rebuilding the parking brake mechanism - including one showing a rivet being removed from a  later 'long arm' 70s DS parking brake.

He clearly knew how to remove the knobs. Surely he had also rebuilt earlier brake mechanisms? Surely he knew how to dismantle them? In desperation I emailed him but heard nothing back.

 

I really wanted an end to this saga now as I was sick of having the thing laying around the workshop. I got to the point where I considered cutting the unit open - just to see how the damn thing was put together - then buying a different unit from elsewhere. I let that thought pass and busied myself with other jobs while I waited for inspiration.

 

Before long I had a backlog of things I wanted to paint up and so added the brake mechanism to them. So, with some carefull cleaning and even more careful masking, I gave the mechanism a new coat of paint. I wrapped a platic bag over the knob and sealed it with a zip tie - which also held the knob against its spring - meaning  could paint more of the locking arm.

Batch painting parts - including the parking brake mechanism

It actually came out very well - just how I wanted it too, though I still felt a little crest-fallen as I was sure I had missed some obvious trick for removing that knob.

Shortly after this - one evening last month - and quite by chance, I stumbled across a Citroen 'Note Technique' ('technical note') that covered the brake pedal - note number 129 from November 1967. And here it is.

Citroen 'Note Technique 129'

You can see that the photo on the front cover highlights a split pin. This note announced to garages that with effect from October 1967, the knob of the pedal unit was now removable. Meaning that - before that date -  it wasn't removable. And there was no split pin! That changeover explained the mixed answers I got back from other D owners and from Sassens and how sassens were able to provide secondhand knobs - some were removable/ fittable. 

 

The note went on to show the parts in the 'new' split pin version and they seemed to operate as I thought they had done Frustratingly, while the note explained how to assemble the new version, the removal/ disassembly instructions were also for this new version - not removing ones like mine.

Being the kind of person I am.... I looked at an earlier parts manual - manual 519 from 1966. This shows that the knob was similar/ same shape as the knob used after 1968. The difference in the diagram is that the knob is not shown exploded into it's component parts - it's not shown as removable from the locking arm.

The 1966 parts manual shows the knob as fixed to the arm

That would be consistent with the introduction of a split pin only from October 1967. I still have a query though: if the ornate style knob was introduced from October 1967, and the technical note says pins were fitted from October 1967 - then shouldn't ALL parking brakes with an ornate knob have a removal pin??

I really do need to put this to bed, and so the conclusion I've reached is that, as in other cases, there was a cross-over period before production settled down - so an ornate knob - but fixed.

And another query: if the 'ornate-but-fixed' design is one of the earliest and pre-October 1967, then how did it come to be fitted to my Feb - April 1968 manufactured car? I guess Citroen have a stock of these parts made up for the production line and just reach into a bin and pull one out.....

Hydraulic Gear Selector - Strip Down and Overhaul (Part 2)

In my last post I covered how I stripped down and rebuilt the main hydraulic gear selector - the 'gear brain'. In this 'part 2' post, I'll cover how I stripped and rebuilt the  gearchange speed regulator. It's a steel bodied, broadly cylindrical unit bolted on top of the gear brain.

The gearchange speed regulator, on top of the 'gear brain'

I'd got as far as seperating the regulator from the main 'gear brain'. 

Gerachange speed regulator, on the gear brain

 Dismantling and rebuilding involves giving the insides a good clean and replacing the rubber ring seals under the hex heads.

The gearchange speed regulator was introduced to deal with changes in fluid temperature and pressure that would otherwise alter how the gear brain responded. Inside, it looks like this.....

The numbers in brackets relate to the part numbers in the rebuild instructions in English manual 518. But there is a 'but'....

 

At this point I need to say that I love English language manual 518. As well as a digital copy, I have two printed copies distributed around the house. It contains loads of information not in later manual 814. It's an essential companion if you carry out work on your DS. Here's the 'but'....as explained in 'part 1', the gearchange rebuild instructions in English language manual 518 contain errors. And those errors are also in the section covering the gearchange speed regulator. I think it was 'Faulksy' over in Australia that pointed this out.

 

It's helpful to set up a couple of conventions so that it is clear what end of the regulator is being discussed. There is a large hex-headed screw at each end of the regulator body. The body itself is a central cubid shape with a cylinder shape on each end. One cylinder end is long (the French rebuild instructions call this end 'a') and the other cylinder end is short (the French manual calls this end 'b'). The vast majority of work takes place through end 'a'. 

 

With the hex head of end 'a' removed, two pieces slide out -  first a piston and then, after that, a spring.

Initial disassembly of my regulator

 Already this can become confusing if you' are being guided by manul 518. The text is correct, but the photo shows the parts laid out differently. Compare my insides to the (incorrect) photo in manual 518!

WRONG: the incorrect photo in English manual 518

Not only does the photo in manual 518 that the spring comes out before the piston, but also the  piston is the wrong way round relative the two ends of the regulator. By comparison, French manual 583 gets it right. (But note how the part numbers are different).

RIGHT: the equivalent photo in French manual 583

The next task was to dismantle the piston to clean the parts inside. In doing so, I noticed that someone - presumably the machinist or maybe someone from quality control - had put their initial on my piston. Is this a fancy 'J'. Jacques? Just for a moment there was a smell of Gauloise in the air..........

Signed with pride?

Access to the piston is gained from a slotted screw in the end of the piston. I emphasise this to draw a distinction between it and another 'slotted screw': behind the hex screw on end 'b' is a slotted adjuster and it should not be adjusted!

Slotted screw in the regulator body. No - do not tinker!

It's basically a variable 'stop' for the end of the spring. This is factory set for each unit and is not meant to be tampered with. Presumably there were slight variations in body engineering and spring strength and each unit is different. Manual 518 tells you not to alter it, but doesn't really make clear where it is.

 

You might have bought a rebuild kit that contains replacement springs, and feel obliged to replace the spring in the the regulator - reasoning that the old spring might be tired and worn. I would advise against replacing it.

Some rebuild kits contain replacement springs

The spring itself is easily removed from end 'a' but think again before being tempted to replace it as there are no available measurements for setting a new spring up. So you will be no better off.

 

Back to the piston from end 'a'. Undoing the slotted screw in the piston end allows you to remove a surprising large number of very small (and easily lost) parts.

Slotted screw in the piston. yes - undo this...

These are a number of thin discs with small holes in them. You will also have a number of small steel rings. these are spacers for the discs. Last, but not least, you will also find a small circular gauze which lives at the far end of the piston.

Gauze in the piston end

In addition to the gauze, I removed 14 discs, 14 spacers and a washer. 

A surprising number of discs and spacers.....

Note that I also had a washer in addition to the 14 spacers. It's the dirty, blackened ring over on the right hand side in the photo above. The manuals and cutaway diagram make no mention of this washer.

 

This series of discs and spacers are what compensate for changes in the viscosity of the hydraulic fluid. Some discs have the holes through the centre. For others, the holes are offset. This is intentional as the zig-zag passage through the holes is intended to 'frustrate the flow of hydraulic fluid.

 

The holes in the discs are easily blocked and so all the parts benefit from a good clean. The parts can be very gently shaken or tapped out. Don't be tempted to use compressed air or anything sharp to force them out from the gauze end, as you risk losing or damaging the discs (and spacers).

I gave all the parts a good wash and clean in petrol. All the holes in the discs looked clear - which is good becase I wanted to avoid the temptation to poke them through with wire or a needle. The discs and piston were also cleaned in my ultra sonic cleaner. The discs are sufficiently big enough to not get lost at the bottom of the clener and I was careful to keep stock of all the parts. I carefully rinsed and dried the parts and gave the internal parts a brush with LHM.

Reassembly is straightforward but again complicated by both the photos and instructions given in the original printed copies of manual 518....... 

First back into the piston is the gauze, followed by a spacer. Next is a disc. I noted in my unit that, when removed, the last disc removed - disc closest to the gauze - was one that had it's hole offset. This is consistent with the cutaway diagram earlier in this post. It's also consistent with French manaual 583. However (surprise surprise) the factory rebuild instructions in manual 518 contradict this and state that the first disc refitted should have a central hole...... Doubting manual 518 I put mine back together as I had found it.

After the disc with offset hole, another spacer, then a disc with a central hole. I continued like this until all 14 disc and 14 spacers were refitted - making sure as each went in that it was lubticated with LHM and that it sat flat on the layer below. The last piece to go in was the washer/ spacer.

 

This is where manual 518 can be confusing. It's the terminology used. Throughout the procedure, the instructions refer to the two external hex screws as 'plugs'. The slotted adjuster (that should not be adjusted!) under the plug at end 'b' is referred-to as a 'screw', and the slotted cap on the end of the piston is referred-to as a 'plug'....For the assembly instructions, the 'plug' in the piston end is now called a 'screw'. It doesn't sound like a big change, but given the incorrect photo and lack of information about what is where, it's easy to get wrong-footed here. Anyway, I replaced the slotted plug/ screw on the end of the piston.....

Screw (or 'plug') in the piston

All good to go.......

The spring was lubricted and fitted inside the regulator. The assembled piston was lubricated and fitted slotted-screw-end first. In other words, it was fitted leaving the the gauze end visible.

 

A new 'O' ring seal was placed in the recess in the body end. These came with the kit for rebuilding the main 'gear brain'.

New seal for the hex cap

The instructions say this should be fitted over the hex screw, but I put mine in the recess of the body as I felt I could be more confident that the plug then sat squarely and sealed when tightened. 

Which brings me to.....another word of caution here: the two hex screws have the same size threads and hex heads - but have diferent profiles to their inner faces. The screw at end 'b' is concave/ recessed inside. The screw for end 'a' is slotted. Manual 518 is again, not helpful here stating only to "fit the plugs in the same positions as they occupied before dismantling" - but not really reminding you which goes where. French manual 583 is more helpful. It omits this instruction and more clearly states that the parts should be refitted "The cap (1) (recessed body in 'c') placed on the side of the relegation screw, in 'b' ".

In a follow up instruction, manual 518 advises "the plug (1) must enter by hand. If it does not, the spring is out of place". Now I also have a problem with this instruction.......referring to the cutaway diagram earlier in this post, 'plug 1' is at end 'b'. And it covers the adjuster screw that should not be adjusted. So why wouldn't plug 1 go back exactly as you removed it? Surely not for any reason to do with the spring?

I think the instruction in 518 (incidentally the instruction isn't in French language manual 583) must be referring to the hex plug (part 4) on end 'a': if the piston has been put in the wrong way round, or the end of the piston has not engaged with the spring, then maybe the piston sticks out a little too far and stops the hex plug (4) being fitted? I don't know for sure, and none of us should really need to be second-guessing Citroen.

I put a new seal at the other end (end 'b') and replaced that hex screw. Surprise surprise, the plug 'entered by hand'.

 

I fitted the  gearchange speed regulator back on top of the 'gear brain'. Masking off holes and studs, it all got splashed with paint.

After masking and painting

I painted the pair of pipes that fit be wtween the gear brain and speed regulator seperately. remebering to fit new sealing rings in the plate.....

New O rings in the pipe sealing plate

........everything was reunited.

All done

Don't be put off manual 518, it really is very helpful to have. Many of it's sections that aren't in manual 814 are finding their way into digital copies of 814. You can tell which they are because the operations tend to be numbered with a 'DX' prefix. But if what the instructions say, and what your eyes are seeing are different: dig a little deeper. Do some cross-checking. Seek out other advice. Don't take things at face value. Bon chance!