Resurrection of my CQ20V

[Bowie69]

Cheers Alex, think I got the part number from that thread: 8A2 612 105A

Though VAGCAT says 893612107A is for a servo, from another thread I say this is apparently an inch bigger, and may not fit the RHD cars... Listed in vagcat for a non-hydroboost car, so confused...?

Also, looking at this page, Does anyone know other bits do I need, there are so many other threads with random postings it is hard to keep track, and am getting brain burn:

http://www.vagcat.com/epc/cat/au/ACO.../54/1447514/#5

#1 Servo (obviously)
#2 Bracket for brake servo
#3 Seal
#5,#6,#7,#10 Clevis arrangement

Pretty sure I will need the clevis arrangement, unless it comes attached to the servo (probably second hand), but not sure about #2, as I already appear to have this plate, and in some of the write ups, this is removed entirely and the servo is bolted directly to the firewall?

Other bits are vacuum hose and a check valve, but they are easy to source

Thanks chaps

Pete.

[Error404]

That part number I posted is the correct one.
You will already have the bracket on your 7A.
You can also reuse the clevis off your hydro servo.
Let me know if you want a rebuilt direct fit single stage PAS pump

HTH

[Bowie69]

Timely.... as pedal stated pulsing again today!

Will get a servo on order I think....

Oh, and to keep the thread up to date, 189,000 miles now, and the fuel pump died two days ago.... new one fitted and back up and running again

[Bowie69]

Bit the bullet, £50 delivered for a servo, pipework, NRV and any brackets (just in case!)

Alex, does your rebuilt pump do away completely with a section of the pump? i.e. the casing is shorter? PM me details

[Bowie69]

So yesterday, my servo arrived apologies for lack of pictures, my phone bricked a week ago and awaiting repair, but will try my best to describe it.

Got the servo from a '95 Cabriolet, complete with a couple of brackets, numbers 11,3,2,4,8,9,10,5,6,7 on this diagram:

http://partscatalog.info/audi/en/?i=...rent_id=534261

When ordering I just asked for the part number, which is clearly visible from the white lucas label on the top. I confirm that the part number is : 8A2 612 105A

Now, while I ordered the whole lot, including the bracket, turns out I didn't need the bracket, however, it does save a little work, given I only paid £50 delivered I was happy.
Bear in mind some of this will only apply to the NA 20V, and also that this is a RHD car

So, starting in the car, press brake pedal around 30 times to get rid of excess pressure in bomb -turns out I forgot to do this, and wasn't necessary, as mine wasn't holding even the slightest bit of pressure

Next, drain the brake fluid reservoir of most of its fluid by removing the clutch master hose, then pull the reservoir off and dump the rest of the fluid into a pot, and not all over the hot exhaust....

Remove the hydraulic fluid return line from the top of the servo, and the feed line from the bottom left of the servo -both are normal 11mm brake unions.

Remove the two bolts that hold the master cylinder to the servo.

Remove the two screws holding the connector for the idle switch and move out the way.

Remove vacuum line from rear of inlet manifold to save it getting mashed, move out the way.

Now in the footwell, remove parcel shelf, and with many wobbly bars and a ratchet, remove the three nuts that hold the servo bracket to the firewall. This is a bit tricky, but nothing like getting them back on!

Remove clevis pin clip, and pin. Remove the spring that attaches to the push rod.

Back in the engine bay, and with the extra wiggle room, remove the master cylinder from the servo, and bend it out the way a bit -the lines will cope as long as you are gentle.

Remove the hydro servo.

With the two servos with brackets sat next to each other, I looked at the push rods and compared length, clevis pin size, bracket width etc... Now the cabriolet servo was more heavy duty in just about every way, and was maybe 3-4mm longer than my old one, measuring from the back of the bracket (where it meets the firewall). Aside from that it was IDENTICAL in all important dimensions. So basically it turned into a direct swap exercise, literally bolt it in and connect it up to the pedal. I left it a little long with a view to adjust it later, but actually it has brought the brake pedal up to the same height as the clutch, always used to be lower, so win-win

So push it in, connect pedal with clevis pin and spring, fit 3 (tricky) nuts to hold the servo to the firewall.

Back in the engine bay, check the o-ring/gasket for the brake master to servo is still there and OK, (part num 357611243, 41.5x2.5mm, square (I think)), mine was a little squashed to opted for a little RTV to make sure, will replace when I get back to the workshop. Fit the master cylinder up to the servo using two nuts this time (my chap had sent them along with everything else), making sure the pushrod goes up inside the tube on the master cylinder.

With my servo I also go the hard vacuum line, maybe this will work with a turbo car, but for mine it was not really ideal, but got me going. I took a vacuum source from the rear of the inlet manifold, the engine side of butterfly -there is a pink vacuum line attached to this from factory (no idea what it does...........?) and joined it up to the servo. I checked the one-way valve was OK my sucking/blowing through the line, and it was

Refit master cylinder brake fluid reservoir.

With that done, time to block off some hoses. I made up an end cap for the return line from the servo using a female brake union, piece of brake line and a hammer/vice to squash the end of the line over, screwed it on, and tightened it up, no leaks It is low pressure here, so no worries doing it this way.

Did the same for the servo feed line.

Next, remove the power steering/tandem pump. Hate this job, especially the silly 14mm slim nut on the adjuster! Need to remove the radiator brace to get enough flex in the radiator cowling to get at this little blighter...

With it off and in the vice, undo the big '+' plugs and pull out the springs, and pistons, clean the opening well and replace the '+' plugs. The pistons are SMALL... was expecting something more than that

Refit pump, I took the chance to drain the fluid as much as I could as the pump was suspect, I wanted to flush out any metal filings(!)

Refill with brake fluid and G004000.

Start the car! Must say it was VERY satisfying starting the car with my foot on the brake and feeling the pedal sink slowly

Think that is about it... I will get some photos up of the installation soon, typical to do something I wanted to document well to have no camera!

Driving experience... well I will say I can see why some people try/do fit the double diaphragm servos, the pedal is quite heavy, when compared to modern cars, and this is on a car with stock brakes. Having said that, it is no more heavy than with the hydro servo, and in fact I am struggling to remember exactly what it was like before having been driving it a fair bit with an intermittent pulsing pedal...

Whole job took me around 3 hours to do, so nothing rocket science/particularly time consuming, faffing with the servo hardline took at least half an hour of that... will go back and replace with a piece of flexible vacuum hose soon.

Alex is hooking me up with replacement single-stage pump, which I am looking forward to Will remove the bomb and associated hoses at the same time.




Now.... yes I do want to keep this original as possible, however dropping best part of £1000 on parts to get the hydro system up and working properly again was not possible, have to be realistic about these things This fix is pretty much permanent and much more repairable/simple and even with a refurbished PAS pump will be way LESS than £250. If my pump was otherwise OK, I wouldn't even bother replacing it, so total cost around £70-80 including fluids, that has to make it a bargain.

[Error404]

Good job.
Your donor pump and ZF seal kit arrived today from Ze Germany so I am on it

[Bowie69]

Cheers alex, that'll finish off the job nicely

[Bowie69]

Aha, found what the pink vacuum line is on back of inlet manifold -it disappears through the firewall just to the right of the battery, and winds its way back to under the rear seat for the diff lock control box

As per this: http://s55.photobucket.com/user/yoda...cans2.jpg.html

Finding this has allowed me to confirm all my hoses are in the right place -just need to find a way to reconnect the diff lock line, alongside the servo

[Error404]

Use a generic nylon Tee off fleabay

[Bowie69]

Yeah, think I have something kicking about from a Rover V8 that'll do

[Bowie69]

Well Saturday was quite a long day, I fitted twin towing electrics to the car, something I have put off for about a year now, it's not a hard job, just always seems to take a lot longer than expected! Found a very convenient grommet in the firewall to pass the power/charging cables into the cabin right by the ignition coil, then ran it down the drivers side under the carpet, made for quite a tidy installation in the end

The day was also interrupted by having lunch out, which ended up taking 5 hours(!), so when it came to fitting the lovely single stage power steering pump from Alex (thank you!), it took me right until 10pm to get the car drivable.

The pump fitted perfectly, as you would expect, also gave me a chance to clean up the side of the engine block from congealed oil, and replace the third oil pressure switch I have had leak on me -grr.... 3 different makes, 3 failures in 2 years!

Once all back together, bled it up and drove it, hurrah, job done.

Next morning I managed to leave a slick on the drive -doh..... turns out I had two leaks! One, the crush washer on the pump inlet must have picked up a bit of dirt and was slightly dimpled so leaking, and 2, a failed hose clip on the power steering rack return line was dripping more than once a second.... all sorted Sunday morning, and sprayed loads of brake cleaner round to remove all the split hydraulic fluid....

Moral of the story, if a job's worth doing, do it with plenty of time in hand, and not in a hurry!

[Bowie69]

Oh, and forgot to say, odometer and trip meter stopped working a coupe of days ago, realised yesterday!

Take it I have to replace that worn gear... I think the strain of going over 190K has done it in

[Error404]

Glad you got the pump fitted mate
Actually I started working on a new PAS project yesterday

Those oil pressure switches are a pain. Noticed my "new" one is weeping yesterday, after the grand total of about 4.5k miles

[Bowie69]

Sounds about par, thats 3 switches for me in 25K miles.... had to look on the MOT history to check that, if anyone knows of a reliable make then I am all ears... this last one I just fitted turned out to be Intermotor, which I do not have high hopes for... the previous one was supposed to be 'contitech', but when delivered was Lemark, to which I sent a snotty ebay message to the seller and got a refund for (and kept the switch!). Barely lasted 5K I reckon.

Thinking about it now, the other failures I've had in that time on such a high mileage car is not actually that bad

List of bits to do at the moment:

Trace occasional smell of fuel, quite possibly fuel lines going crusty
Check front end for a couple of clunks (yes again)
Front alignment (yes again!)
2 front tyres very soon
Sort some rattles -mainly driver's door and the roof lining rattles against the sunroof

In amongst all this I've moved home and been renovating a house, so time has been a bit short!

Oh, and a VERY long running problem -surging idle when cold. Have been through and replaced/tested ISVs multiple times, checked all the vacuum lines, set base idles umpteen times, disconnected carbon canister, and when I replaced the rocker gasket, I did the inlet manifold gasket at the same time, so as far as I can see there are NO induction leaks the wrong side of the AFM, yet it still does it... This has gone on for about 50K now, so not really a major problem, just an itch that I have been unable to scratch...

[Bowie69]

New gear for the odometer arrived this morning (thanks Greg_S!) Hopefully get fitted this weekend.