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.....allows the cable to be withdrawn.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