Brake Fluid - "Pumpin' or Blowin'"? - rg

I see from another thred that opinions are divided on the method of changing brake fluid.

I am struggling to understand how simply topping up and pumping (with care with the pedal) would cause the brakes to subsequently be soft. Surely one stream of fluid is simply following another if the reservoir is kept topped up? Or am I missing something? (like "grey matter"?)

Now, if a caliper, hose, or pipe had been replaced, and air could have got everywhere, then I could understand the need to use the Gunson pressure device to "blow" the fluid in.

I am about to embark on changing the fluid on the Trooper/Monterey, and wonder about shelling out the £15-ish for the Gunson tool (maybe more if I need a special cap adapter).

Maybe this is where the Citroen has the edge, which, for all its electro-hydraulic fun, has, (so I read repeatedly on other forum) a virtually self-bleeding system, save for the "cul-de-sac" of each caliper.

Suggestions from list sages welcome!

Brake Fluid - - Andrew Moorey (Tune-Up)
Rob, I routinely use an Eezibleed to change brake fluid. Use about 10psi and you wont get fluid everywhere, oh, and before you start draw off as much of the old fluid as possible from the reservoir with a syringe or similar then fill 3/4 with fresh before attaching the device. Bleed about1/2 the bottle from the first (furthest) point then the remaining 1/2 through the other three. On the final one allow the bottle to just empty and clear the tube before closing the last nipple then depressurise and remove the device with hopefully little or no spillage of fluid.

Simplicate and add lightness!
Pumpin' Blowin' or Suckin'? - pmh
I hope this does not find the censors read pen!

Read Aprilias comments about the sucking option in the following thread, this raised some questions but not definitive answers.

I have always used Easibleed but now wonder whether to try the suckin' option.

pmh (was peter)
Brake Fluid - - RichardW
>Maybe this is where the Citroen has the edge, which, for all >its electro-hydraulic fun, has, (so I read repeatedly on other >forum) a virtually self-bleeding system, save for the "cul-de->sac" of each caliper.

Even bleeding the brakes on hydraulic Cits is easy - start engine, wedge brake pedal down (block of wood off driver's seat) and simply go round and open the bleed screws in turn. Plenty of pressure available to blast the fluid out....


Brake Fluid - - rg
Cits have the advantage of 1500psi...

An aircraft engineer on the Yahoo XM forum says that the hydraulics of the XM and aircraft systems are not that dissimilar..

Brake Fluid - - glowplug
The soft pedal thing could come from the fact that the pistons/seals travel further than normal and so come into contact with a corroded part of the cylinder, this could damage the seals with the associated consequences.

I've used the suck method on a motorcycle and found it very effective.

Brake Fluid - - Claude
Some vehicles (and some ABS) are very difficult to bleed wthout using a pressure bleeder. But in any event, once you have used one you'll never go back to pumping the brake pedal or wedging it with pieces of wood! Unless you have one person on the pedal and the other being careful to shut off the bleed nipple at the end of every pedal stroke it is very easy for air to creep into the system. You may have the end of the bleed tube in a jar of fluid or be using a one way valve but air WILL get in down the threads of the bleed nipple on the return stroke unless the nipple is closed at the end of each down stroke. Of course most of it would have bled out again on the next down stroke but the piston in the brake cylinder is working backwards and forwards and maybe not all of it will be bled out. But pressure bleeding guarantees that there will be NO air in the system, all the pistons will have remained static during the bleeding process, you only need one person and its takes less time.
Brake Fluid - - rg

Thanks very much for providing an important snippet of information regarding the air via the nipple threads. It now makes sense.

I have replaced the whole pipework system on my 405 before, plus changed calipers, but this was non-ABS and returned to a firm pedal with no trouble.

XM build quality:- "it adds to their character, sir".

The worst application of an automotive engine to aviation IMHO was a gyrocopter powered by a Triumph 650 vertical twin.

The pilot can't glide -that-far in a gyrocopter. Gravity tends to win.

And the Triumph twin was famous for throwing its rods, blowing a gasket and seizing, or a comination of both...

Cheers, all

Brake Fluid - - Armitage Shanks{P}
Luckily the build qualitty and reliability of aircraft are considerably better than those of an XM though!!
Brake Fluid - - madf
"Cits have the advantage of 1500psi...

An aircraft engineer on the Yahoo XM forum says that the hydraulics of the XM and aircraft systems are not that dissimilar"

Most automotive engineers would say that the electrics of the XM and a Heath Robinson device are also not dissimilar except the latter tend to be more reliable.:-)

To compare an XM and an aeroplane in terms of quality requires the mindset of an XM owner who is fanatic: I assume any owner has to be: the rest of us prefer cars that are reasonably reliable...
Brake Fluid - - rg

It's great to see that the preconceptions and misconceptions are still alive and well.

They served to drive down the market value of the XM, meaning that, provided they are bought carefully, owners end up with a unique, reliable car which is an absolute bargain.

Please keep up the good work.

And we'll keep on enjoying...

Brake Fluid - - Malcolm_L

Pumpin is the only somewhat tenuous link to the original thread now!

Totally agree with your comments about misconceptions, I had 5 Citroens 1 CX, 3 BX's and a Xantia, other than the usual brakes/tyres these were totally reliable.
The build quality was no worse than any equivalent car and given their additional complexity probably somewhat better.
(Oops - I fibbed - last BX 1.9 GTI auto burned the torque convertor out in Bristol - however this was replaced under warranty even at 38000 miles, I did have to pay for the fluids though!)
This was one of the worse engine gearbox mismatches I've ever come across, too little torque at low speeds and too juicy at higher revs, damn noisy too.

The CX was a pig to work on (having something resembling a young Forth bridge between the engine and the bulkhead didn't help).

C5 doesn't ring my bell - styling is too bland, Xantia actually looked good when it came out.

Still enjoying...

"Citroens Break Down" Shock.. - rg
The following posted on the XM forum by Duncan Bryan.:


Fatal to say it but... my XM (2.5TX VSX) has not had any unexpected faults
over 40K miles.
I wish I could say that same about my wife's A-Class Merc A160.

N reg XM problems over past 2 years.
1. A tyre - puncture :-(
2. A set of spheres. Pleiades tastic.
3. A cam belt
4. about 8 oil and filter changes - air filter as well of course.
5. 3 diesel filter changes ( phew - not due next time )
6. A gallon of hydraflush
7. A door mirror temp sensor.. grrrr
8. A keyfob outer.
Mileage now - just shy of 92K
Mileage covered - about 40K
Time unavailable over 2 years - 1 day - for cambelt change.
Cost - about 900...sigh.
2.25p/mile costs

Depreciation. probably about 3000 lost.

T-reg Merc A160 over same time.

1. New petrol gauge sender ( warranty)
2. New rear wheel - it hit a pothole ( I hit the same one in the XM )
3. Four new tyres ( in 2 stages)
4. Anti-roll bar drop links ( front)
5. Left rear radius arm ( 4 months ago)
6. Right rear radius arm ( this Friday)
7. New petrol gauge sender - needed again soon.
8. Rear door window ( not that car's fault)
9. 3 services ( one of which missed the bent wheel!!!!!)
Mileage now - just shy of 26K miles
Time unavailable over 2 years - about 5 days.
Cost - about 900
mileage covered - about 15K miles
6p/mile costs

Depreciation - probably about 5000 lost.



Value my car