It really isn't rocket science.

[Prilliant03]

After much procrastination I finally got around to replacing the accumulator sphere on my Xantia HDi 110 today. I've been dreading this job, fearing all manner of mechanical mayhem.

Anyway, to cut a long story short, the job ended up taking all of 30 minutes. Once I had removed the plastic engine covers and displaces an air hose I was easily able to access the accumulator from above, so no need for axel stands and crawling around on a cold floor.

My click interval has now gone from 10 seconds to ............. well, I stopped bothering to count at 45 seconds. My brakes are also working a lot more consistently now. I think we can call that a result

One little question. I would like to bleed my brakes properly and was wondering if it's ok to use a vacuum pump on these cars. I have a Mityvac that I bought for bleeding the brakes on my bike and it's a fantastic bit of kit. Any reason why it wouldn't work?

[Lighty]

There is no need for a Mityvac, great as they are. Just apply the brakes with the engine running ( you will need the rear suspension to be bearing weight or in high position).
Then go around the nipples one at a time, and fluid will come out in a continuous flow.

[DickieG]

One little question. I would like to bleed my brakes properly and was wondering if it's ok to use a vacuum pump on these cars. I have a Mityvac that I bought for bleeding the brakes on my bike and it's a fantastic bit of kit. Any reason why it wouldn't work?

Firstly there's no point in using such a tool as Xantia brakes are bled by having the engine running, getting someone (or a wedged broom handle) to push and hold down the brake pedal then undo each bleed nipple and fluid will flow freely, the difference with these brakes is that pushing down on the brake pedal does not push fluid down the brake pipes, it merely opens a valve to allow already pressurised fluid (LHM) to pass through the "master cylinder".

Whether your pressure tool would work at all without someone/thing pushing on the brake pedal is a question I can't answer, I suspect it may not but there's one way of finding out!

[Prilliant03]

Much appreciated gents. Sounds fairly straightforward. I'll at that to tomorrow's "to do" list.

[myglaren]

Have a read through this thread to familiarise yourself with the hydraulic system and its maintenance.

Brake bleeding is an absolute doddle in comparison to conventional systems.

[CitroJim]

Good work An accumulator on an HDi is nicely easily accessible compared to some but you were fortunate that it came off nice and easy. Sometimes they can be so tight they need rather a lot of persuasion - sometimes involving a big hammer and chisel What tool did you use to get the old one off?

Once you've bled the brakes you'll never want to faff around with those conventional brake systems ever again. Bleed nipples hardly (if) ever seize and the whole job is a joy. It makes the conventional servo/master cylinder/brake fluid setup look positively anachronistic.

[andpand]

sorry to butt in here but does this method work on a c5 hdi aswell

[Dommo]

Unfortunately not andpand, they changed the brake system from the one described above that had been used since the DS to a 'normal' (bad) system on the C5 and C6, fools!!

[myglaren]

Unfortunately not andpand, they changed the brake system from the one described above that had been used since the DS to a 'normal' (bad) system on the C5 and C6, fools!!

I was hugely disappointed to find that they weren't proper Citroen brakes but they do work rather well.

[Xaccers]

Anyway, to cut a long story short, the job ended up taking all of 30 minutes. Once I had removed the plastic engine covers and displaces an air hose I was easily able to access the accumulator from above, so no need for axel stands and crawling around on a cold floor.

The hydraulics system really is simple, it's just fluid flowing through pipes with a few shuttle valves for the height correction (mechanically controlled so they either work or something has broken/seized and therefore easy to fix) and the doseur valve that controls the brakes is basically a stopcock that the pedal presses directly on to open it.
You can renew your front suspension in 20-30 minutes, and rears in not much longer, without any risk of nasty compressed springs taking your eye out (and the ride is a damn sight better!)

It's like changing a wheel on a Xantia is so much easier than a sprung car, you just bring the jack up to the jacking point by the wheel that needs changing, or an axle stand, set the car on low and it lifts the wheel off the ground for you (so slacken the wheel bolts slightly before you do that), none of this need to lift the car with a jack

[CitroJim]

I wonder if it was impending legislation that caused Citroen to abandon full hydraulic braking on the C5 and C6.

Strictly, they're not dual-circuit and failsafe in the same way as a conventional braking system is. OK so the dosuer valve is split front and back and a burst front flexi say, might allow the rear to carry on working but if all hydrauluic pressure is lost then that's it. No brakes. OK, so the front and rear accumulators might give a few applications but only until they flatten. The problem is the common source of pressure for front and rear and there being no purely mechanical brake actuation as you have in a conventional master cylinder. There the servo can fail and a pipe to any brake can burst but you'll have brakes of a sort even with no engine running just as long as there's fluid in the system. Citron hydraulic brakes can't meet that level of failsafe.

All speculation on my part but that may be why too the Xantia's life was cut short compared to the Pug 406 which lasted a good few years longer despite being basically the same car but with conventional brakes and springs.

It's pretty clear, looking at the last Mk2 Xantias that some quite significant changes were made very late in production. Why go to the expense if the car was soon to be superseded? I believe the Xantia was pulled at least two years early and that the early C5 was a bit hastily rushed into production.

[andpand]

Unfortunately not andpand, they changed the brake system from the one described above that had been used since the DS to a 'normal' (bad) system on the C5 and C6, fools!!

thats a shame why change a method that worked

[Prilliant03]

Citrojim, I ordered the shere removal tool that was listed on EBay. A few comments on here had me worried that it might not be man enough for the job, but it seems to be very solid and has a sturdy brace welded in to resist bending. Got my sphere from GSF and will definitely deal with them again. Just a shame their website is so bad. I'm sure it puts some people off dealing with them.

I also bought a litre of LHM fluid from my local Halfords but would like to pehaps buy a 5 litre container to have in the garage. Is there a good source for LHM where I won't be paying £11+ per litre?

[Xaccers]

our local dealer is about £6 a litre of LHM, I think GSF do it for a bit less.
Halfrauds is one of the most expensive.

[Prilliant03]

Yeah, I knew Halfrauds would be a bit spendy, but it was a case of any port in a storm on saturday morning. Lots to do and little time to do it. I took the easy option.