Disc Brake Calipers And Final Preparations

 

 This isn't very visual at all, as I was too busy to take any photos.

 

Re-acquainting the engine and chassis

The engine needed to be moved from my workshop into the garage. Not as straightforward as it sounds.  A DS is long and with the car in the garage, there was little room to get anything through the doorway. Though believe me - having a little workshop next to the garage is so useful. Cue gratuitous shot of my garage......

Garage.... and workshop beyond

First of all, the car had to be moved back out of the garage to make the room needed to wheel the engine through from next door...... I removed the rear spheres and popped a couple of short broom handle lengths in the the rear cylinders to hold the rear suspension up. 

Wooden rods used to prop up the suspension

With that done I was able to inflate and fit a couple of (very) old rear wheels/ tyres and remove the axle stands. I didn't fit the front wheels. I was worried that the rotation of the 'limp' drive shafts (no engine fitted yet) would tear my newly fitted drive shaft gaiters on the chassis. So, instead, I just raised a  trolley jack under the beam that goes across the engine bay and used that to help move the car the three or four feet needed.

 

My home made engine stand was wheeled out of it's corner in the workshop. It had been in there so long. Years. 

My homemade engine stand had served me well

My trolley had rubber tyres on it's castors and I'd found that the combined weight of the engine and gearbox squashed the tyres and made the trolley nearly impossible to move. That was one of the reasons I'd delayed fitting the brakes to the engine; to keep the weight down! With some difficulty and a number of 'three-point turns' I navigated the doorway to the garage. I felt like NASA moving a Saturn V to the launch pad!  

 

Temporarily swapping places with my compressor, for the first time in many years the engine and car were back in the same room. With the  trolley jack under the front of the chassis again,  I moved the car back into the garage. In hindsight it was VERY high risk as the car could easily have fallen off that jack and damaged itself - if not me. As it was, I got away with it. The front of the car was put back on axle stands while I did the last few jobs to the engine. With tomorrow being the 'big day' when I planned to put the engine back in the car,  those brake calipers had to be fitted......

 

Brake Calipers

There is a bit of a technique to fitting the callipers to the car. With the engine out of the car the brake callipers are fast and easy to fit. That's right: I didn't find time to take any photos...... I'll have to use some scrounged images.

 

The procedure for refitting the callipers is covered in Operation DX.451-1 in manual 518. Some PDF copies of manual 814, have a similar operation - Operation DJ.451-1 included in volume 2. Other than 'DJ' being for manual gear change cars, the basic process is the same.

 

The units should be bolted the car only hand-tight to start with. I must have fitted the discs over the half shafts, then slotted the calipes on. and calipers on I guess. But that really was all I could do at this stage. First scrounged photo coming up.....

The securing bolts are ringed

Until the engine is in the car and all the hyraulics are connected up, I can't finish the fitting: with the engine running, you need to get someone to apply the brakes. This causes the pads to contact the discs and (with the bolts only hand tight), the hyraulic pressure causes the calliper units adjust their position so that the pads contact the discs 'flat' and evenly. With the brakes still on,  held on, the calliper units bolts can be tightened to maintain that position.

Making A Hydraulic Pipe (again)

I hadn't been planning to do this. In fitting the brake calipers, I found I had to re-make a long and complicated hydraulic pipe that went from the 'accelerated idling control' on the carburetor, all the way to the n/s brake caliper. I think it's the pipe for bleeding the left hand side brake. I've marked it on this photo.

 The first one I'd made had been too short to reach the disc brake caliper!*! The pipe needed to curve around the parking brake caliper without touching it and that meant it didn't then reach the disc brake caliper with enough 'spare to be able to screw in the flare nut. It was short by about 2cm! I've used this photo before, but it shows the pipe in question.

The pipe around the parking brake caliper was too short!

The pipe follows a complicated route along the side of the block and was threaded behind other pipes so even more pipework and clips had to come off the car for me to fit it. It shares a securing sot with the 6.35mm pipe between the pressure regulator and the hydraulic pump. It's not wise to bend and weaken that pipe, so it had to be completely removed to allow me to work on this other pipe....As well as being difficult to remove (stop complaining Paul. It would be harder with the engine IN the car!), as I shaped the replacement, I kept having to do 'trial fits'. 

 

Front Engine Crossmember

With the calipers fitted, I also re-assembled and fitted the front engine crossmember - the beam that goes across the top of the gearbox. The middle of the crossmember is a kind of 'sandwhich' with segmeted (castellated?) rubber half-bushes held to the main beam by two metal half-collars.

Front engine mount. The rubber 'sandwich' filling is parts 5 and 8

The middle section bolts to the engine/ gearbox and the rubber half-bushes in the sandwich isolates that bolted part from the beam that is bolted to the chassis. In that way, engine vibration and noises is kept from the chassis.

 

There are two brackets (numbered '3' in the drawing above) that bolt through the rubber 'daiblos' in the disc brake calipers. That also helps to absorb some vibration.

The rubber 'diablos' and bushes in the brake calipers

Why are they called 'diablos'? It's because the shape is similar to the prop you see jugglers used at circuses and is a kind of Chines yo-yo. No - really! Anyway, the only photos I have of those brackets are some last minute cleaning before repainting, but they look like this.

There aren't many pieces to the crossmember but they do only fit together one way: the engine doesn't sit in the middle of the engine bay and so the sandwich/ collar in the middle is 'handed' - it's not symetrical. If the collar is assembed on the crossmember the wrong way round, then when the assembly is bolted to the engine, the collar will not fit the curvature of the crossmember  and it will be at the wrong angle......

Assembled wrongly.....(photo credit unknown)

This is how it should be.

Corrected! (photo credit unknown)

I was wise to this when I assembled mine - meaning I'm free to make a whole bunch of different and unrelated mistakes later on. And I'm sure I will! Anyway, this is mine (admittedly after the engine was back in the car). You can see the two holes that the radiator feet will bolt in to.

As well as the brackets providing the holes for the radiator feet, the left hand end of the crossmember also provides the location for bolting the LHM reservoir support to.

The resrvoir support bolts to the welded nut here

And on my 1968 car, the right hand end of the crossmember is also the fixing point for the front leg of my battery tray.

On my 1968 car, the battery tray goes here

 So many more jobs and milestones are going to be possible once the engine is in!

Parking Brake Mechanisms - Stripdown and Overhaul

In the build up to dropping the engine in, I've been doing a few small last minute jobs. In some cases these are things I forgot I would have to do!

 

Parking brake unit refitted

I was so 'in the zone' that I didn't really take any photos of this job. There's not much to it but some photos might have helped to demystify things. I've had to use photos from all over the place. Dago Langen has been particularly kind in letting me use the photos that he took. I'm glad one of us remembered!

 

For some reason, replacement of the calipers wasn't included in the '814' repair manual. But if you are lucky, it might have been added to your PDF version of manual 814. If so, it will be at section 1 in volume 2 and shown as Operation DX.454-1. If it's not there, it can be found at Operation DX.454-1 in manual 518.

 

Even when you find it, you will see it just that - replacement of the calipers. Off and back on. It doesn't go any deeper than that. For example on changing the pads and fitting the anti-rattle springs.There aren't many parts, but it can be confusing trying to put them all back together.

Exploding diagram of the parking brake mechanism

On each side of the car, a pair of log arms (part 4) pivots on a shaft that is part of the caliper body. The brake pads (3) are fitted to the top half of the arms and when the cable pulls the arms together, it pulls the pads on to the disc. Strong springs (5) fitted to the cable push the arms apart again once the brake is released.

The cable pulls the arms together (photo: Dago Langen)

There is a bolt and lock nut through each arm to adjust the brake pads (not numbered in the diagram). These are VERY difficult to access when the engine is in the car.

The adjusters are awkward to access from any angle - even under the car

To hold the pads steady on the arms, each pad has a slot at one end that locates onto part of the main caliper body. That's really just to stabilse the arm and so the pad and arm pivot slightly. The pad needs to be able to move without it's slot binding or catching. To stop each pad rattling as you drive along, 'anti-rattle springs' (3) are fitted in the slots.

 

It's not an issue for me as my car is a 'proper' left hand drive car, but the 1968 parts catalogue shows that for a right hand drive car, there are a combination of three differnt lever arms used: a pair and two that must be handed......Other catalogues show different combinations of parts. The bottom line is that, if you have a RHD car, be careful you don't muddle your lever arms!

The part numbers show that, for RHD cars, the lever arm parts are 'handed'

The calipers of my car had been removed, dismanted, cleaned and primed when? 2015? Probably! Mine weren't quite as mucky as these, but you can see how the road muck can easily stop the brake mechanisms working as intended.

Parking brake unit removed (photo: Dago Langen)

It's hard to see, but there is a split pin on the end of each shaft. When those are taken out, the arms can be removed. And with the arms out of the way, the brake pads can be removed. You might find that small 'anti-rattle spings' also fall out.

Parking brake 'anti-rattle' springs

All the parts were degreased and any rust was removed. I paid particular attention to the shafts that the arms pivot on. as well as the bosses that the slots of the pads fit over. I bulk-sprayed some parts it included parking brake parts, even though I didn't assemble them at the time.

 

I cleaned up the threads of the adjuster bolts. These bolts are fairly specialised in that the hex head is very shallow. I suppose that if you needed such a bolt, you could grind down the head of a standard bolt.

The pads are the first things to be fitted. The pads I'd removed from mine back then were hardly worn but I was worried about them having oil or LHM on the surfaces. By chance someone was selling an unwanted new set at the D rally in June this year and so I bought those. I think that was probably the nudge I needed to remind me I still needed to do this job.

I chose not to re-se these pads but have hung on to them

I put a little copper grease on the bosses that the pads slot on to, just so the pads moved more easily. This partly to allow for ajustment and partly to compensate for wear - though there isn't really any of that. I winkled the anti-rattle springs back in the gap in the slot. 

Note the anti-rattle spring in the slot (photo: Dago Langen)

The factory says there are FOUR anti-rattle springs to a car - that's just one per pad. Because of the way they fit, it feels odd to only attach a spring to one side of a pad and it's tempting to think that each would have two (one either side of the mount) but that is not what Citroen intended, and you will struggle to fit more than one spring per pad in the slot.

I attached the adjuster bolts to the arms. I put a little grease on the threads to make them easier to adjust in due course. I wound the bolts on as far they would go at this stage and only loosely fitted their lock nuts.

Adjuster bolts (photo: Dago Langen)

The arms were fitted on their shafts. It's important that the lever arms can pivot freely. I found that with my enthusisatic painting, they were sticking on the pivots, so the pivots and the holes through the arms got a rub down with emery cloth. The parts books show that the levers have a bush going through them (part 7 in the diagram above), but I didn't notice them on my parts. Perhaps they are pressed in? Happy that the arms moved freely, and that the pads could slide on their bosses, I fitted the split pins to secure the arms in place.

 

Before fitting the calipers to the bellhousing, I used carb cleaner to clean the pad surfaces, and the disc brakes. I offered up the calipers, slipping them over the disk brakes, and put the securing bolts on just hand tight at this stage. 

 

While I had the opportunity, I adjusted the pads with the adjuster bolts so that they just contacted the disc brake. The manual says there should be a 0.1 mm gap between the disc and pad. I tried that but bcause of 'run out' on the discs ('warp' if you will) a 0.1mm clearance at one point left the pad rubbing when the disc was rotated. So I adjsuted my pads so that, when the disc was rotated, the pads *just'* cleared the disc in all places. I didn't tighten the locking nuts just yet.

 

The manual says that the order of jobs should be:

- Loosely fit the calipers

- Fit the parking brake cable and springs

- Tighten the calipers

- Adjust the pads

- Check the cable adjustment.

 

The only problem was that my engine was out of the car - so I couldn't fit the cable just yet so needed to skip that. You don't want the caliper bodies to rub on the rims of the discs. The workshop manual says that there should be a gap of 4mm between the edge of the disc rim  and the arch of the caliper body. 

Caliper assembly fitted (photo: Dago Langen)

I followed Dago's lead: the easiest way to set the gap is to gently wedge a screwdriver in between the disc edge and the brake unit......

Make sure there is a gap before tightening the caliper units (photo: Dago Langen)

.....while tightening the brake unit bolts. The bolts needed to be tightened to a torque of between 10 and 11m.kg.

Tightening the brake units (photo: Dago Langen)

Once the caliper units were in place I re-checked the adjustment of the pads. When setting the adjustment, the manual says that the caliper arms should be pulled together. I checked and made a couple of adjustments. Maybe I was fussing, maybe the calipers had settled in a different spot. I checked that everything moved as intended and that was that for the moment.

I won't be able to refit the operating cable and springs until the engine goes  back into the car - that's happening tomorrow!