servo

[dubberatlast]

Hi all ive took my 1972 bay for the mot today and its failed

heres the list.
offside headlamp aim to high
nearside headlamp aim to low
both rear brakes binding
Brake has no servo assistance


Everything is easy except the servo, do i need a new one, ive got the return valve in the pipe that gos to the inlet manifold if i turn i take it out turn it around the pedal sinks to the floor and the breakes stay on, if i turn it the other way the pedal is realy soft, is the servo fooked :?: or is it something simple :idea: please help its in for retest sat morn and im starting to loose faith

 

[easy]

dude, dont loose face. Headlamps are easy to change just park in front of a wall or the like and adjust accordingly.

As for the servo, it could be a number of things, but check here for more info. http://www.volkszone.com/VZi/archive/index.php/t-352329.html

sounds like maybe a return valve needs sorting, if you are not far away from Whitchurch, give Martin at Bristol Cherished cars a call and he will be able to help you. Go here http://www.bristolcherishedcars.co.uk/ tell him that easy from The Old Volks Club suggested him. Hes a great bloke and comes to you if needed.

 

[dubberatlast]

Cheers dude im a member of dbs in weston so no martin i will give him a shout if get stuck, the servos all sorted now i think ive turned the non return valve round so the arrows pointing towards the engine and sealed all the pipe connections, now the pedal is rock solid but dosnt sink to the floor when i start the engine, when i take my foot of with the engine running it stays down a little then when i turn the engine of the pedal comes back up is this right do you think :?:

 

[VWAIRCOOLED]

The way they test the servo in the mot station is as follows.Turn Engine off,pump brake pedal up and down until vacuum is lost from servo,pedal should go solid.Hold pressure on the pedal then start the engine up.Pedal should then go down a couple of inches or so,but not so much that there is no reserve pedal travel left.

If it does that ok then you will be ok.Some time during the test they will also check the efficiencies of the brakes on the roller.

I won't have this problem with drum brakes and no servo!

Good luck!

 

[dubberatlast]

Right if worst comes to the worst how hard is it to remove the servo so its back to just using the master cylinder and what sort of price am i looking to do this little conversion :wink:

 

[VWAIRCOOLED]

Just looked at you project thread,good wotk dude.
To remove the servo is no big deal but you will need to get a different master cylinder for non servo brakes and just remove the old servo and master and blank the vacuum from the inlet on the engine.Oh and bleed the brakes through.

 

[dubberatlast]

Cool cheers dude got a couple things to try but if they fail then i will have to remove the master cylinder what year master cylinder would i need any ideas

 

[VWAIRCOOLED]

Looks like you will need a 1971> without servo for about £39.95 from vw heritage if you go that way.
I would have a look at the servo pipework first though.The rubber parts can collapse inside and you can't see it.Does it feel a bit soft anywhere? Even then it can collapse and feel ok from the outside.

How is it working at the moment? If you can get a vacuum gauge that would be handy to check the vacuum you are getting from the engine.Also you can get a vacuum pump and connect it to the servo ,pump it up and check the vacuum holds ok.

 

[dubberatlast]

Ive put brand new pipe from front to rear and a new non return valve, now when the vans running the pedal applys the breakes its self, if i rev the engine the pedal comes back up a little but the breakes still are on as i cant move the van, when i switch of the engine the pedal returns to its normal position :?

 

[VWAIRCOOLED]

It is hard to tell exactly what is going on there. is this a standard set up or has someone added it on? Did it ever work properly?

Does sound like the diaphragm in the servo is week though.How does the engine run? Are the rear brakes adjusted perfectly and the rod which goes from servo to master set ok and is the return spring still ok?

 

[VWAIRCOOLED]

One other thing,is it all the brakes lock up or just the rears or just the fronts?

Just found this on type2.com. (for testing booster brakes)


Things you need:

Vacuum guage
Cap for vacuum port on the intake manifold
Friend to work brake pedal
Pencil and paper
Procedure:

Hook up the vac guage. Start the engine. Note the reading. This is your "base" reading.

Stop the engine, disconnect the booster vacuum line and cap the port on the manifold. Start the engine, look at the guage. If this reading is substantally higher than the base, you have a leak in the system, probably in the lines leading to the booster.

Stop the engine, remove and test the one-way valve (should be able to blow into it one way but not the other). Air should only pass in the direction indicated by the arrow printed on the top of the valve (make sure to reinstall it in the correct direction).

Reconnect the one way valve and vacuum line to the manifold and start the engine. Watch the vac guage as a friend depresses the brake pedal. It should dip as the pedal is depressed and return to the base reading. If it drops slowly, but returns, you have a blockage/collapse in the vac line. If it falls and does not return, you have a torn diaphram in the booster. Especially indicative of a torn diaphram is a hissing when the pedal is depressed.

 

[dubberatlast]

Cheers dude ive tried everything i can think of today and its the servo.
I want to put it back to just master cylinder, any ideas how easy a job it is, the servo is of but i dont no what bits i need to order, which master cylinder and hard line kit and anything else i need. i no there pains to bleed to ive been told

 

[VWAIRCOOLED]

I couldn't tell you how easy it is.I would think it better to replace the servo than change it to the other type master cylinder.
As far as I can tell there is one pipe going to front brakes and one going to rear brakes on both systems which should have the same fitments but maybe at slightly different positions/angles.The reservoirs should be the same.the problem might be in the fitment,your type fits on to the servo which fits on to the beam.Non servo types are fitted on the cross member.I suspect the pedal lever will be the same but you will need an operating rod and securing pin.Have you got the holes drilled in the cross member to fit a master cylinder? If so will the pipes stretch over to fit in it's new home?

 

[dubberatlast]

It use to be a non servo model bay so all the holes are there but i need to get the right pipes which means i need to order a new hardline kit as i will replace all the break lines why im there, its the rod from the pedol to the non servo master cylinder im stuck on finding, the rest ive decided to buy new unless someone has a realy good complete secound hand setup theyve took of :wink:

 

[VWAIRCOOLED]

Have you tried to source one from the likes of volksheaven,FBI etc?

 

[dubberatlast]

Im gonna do a load of ringing about in the morn and the missis is going to council the retest and book it for thursday so ive got to get it all ordered and fitted, easy if i can find the bar.

cheers for all your help dude you been great help :wink: