Fitting a remote dual brake servo

[raveboy]

Hey peeps, :mrgreen:

Thinking about fitting a remote dual servo to my braking system. I've read that it will enhance the standard drums all round
considerably. My questions are a: Has anyone else done this and b: How and where did you take the 10mm vacuum from ?
I was thinking of just drill and tapping one side of the manifold (Single port manifold) with the flange airflow slightly angled towards
the head so the vacuum flows better.

Any thoughts peeps ?

The dual servo I was gonna get was this one .
http://www.vwjim.co.uk/ourshop/prod_1182508-Brake-Servo.html

Cheers,
Raver arty0046:

 

[Trikky2]

I cant see any reason why this would not work.

VW used to have the vac takeoff on the manifold a few cm below where the carb bolted on but there is absolutely no reason why you should not take the vac from the end of the manifold as you suggest.

You are right about tilting the vac take-off. Not because it helps the flow but because it will stop fuel mixture from entering the vac system.

Try to make sure your vac take-off stub does not intrude into the manifold since it would cause unwanted turbulence.

 

[lard]

Mine worked fine with the vac take off on one end manifold - shame you have sp as I have a set of tp manifolds with one already braised up with the connector!

 

[r73]

What do you reckon is better - servo drum brakes or non servo late bay discs?
I have good things about these brake servo set ups 8)

 

[raveboy]

Thanks for responces guys, I'll post pictures up of my progress when I start doing it :mrgreen: :mrgreen:

 

[Geeze]

What do you reckon is better - servo drum brakes or non servo late bay discs?
I have good things about these brake servo set ups 8)

I've only driven servo'd drums on a split (but the brakes are pretty much the same) and they're impressive.
The only concern is that you have to know the limitations of drums (ie. fade) as the extra power makes is much easier to cook them.

 

[cunning plan]

Thanks for responces guys, I'll post pictures up of my progress when I start doing it :mrgreen: :mrgreen:

Please do, I would be interested to see. :shadey:

 

[lilblue1970]

Just to clarify, a servo won't improve the performance of the brakes, it will just make them easier to operate. I've got rear drums and non-servo discs on the front and if I slam on, she will stand on her nose. I just make sure I check the brakes regularly and adjust accordingly. Fitting a servo is a bit of a job and I've never seen the benefit of them. More stuff to go wrong.

 

[r73]

Just to clarify, a servo won't improve the performance of the brakes, it will just make them easier to operate. I've got rear drums and non-servo discs on the front and if I slam on, she will stand on her nose. I just make sure I check the brakes regularly and adjust accordingly. Fitting a servo is a bit of a job and I've never seen the benefit of them. More stuff to go wrong.

Ok , have you got a late bay disc setup? Just heard mixed reports about how much better they are than a well set up drum brake :?

 

[naskeet]

I cant see any reason why this would not work.

VW used to have the vac takeoff on the manifold a few cm below where the carb bolted on but there is absolutely no reason why you should not take the vac from the end of the manifold as you suggest.

You are right about tilting the vac take-off. Not because it helps the flow but because it will stop fuel mixture from entering the vac system.

Try to make sure your vac take-off stub does not intrude into the manifold since it would cause unwanted turbulence.

For the 1980~83 VW 1600 Type 25 engine, with twin-port cylinder heads, the vacuum take-off, if fitted, was from bifurcation, of the aluminium-alloy, inlet manifold casting, close to the cylinder head.

http://s13.photobucket.com/albums/a252/dubdazeuk/1600%20CT%20engine%20and%20parts/?action=view&current=IMG_0016.jpg" onclick="window.open(this.href);return false;

My 1972/73 VW 1600 Type 2, was retro-fitted in 1988/89, with a pair of remote-acting, vacuum brake servo units, mounted in a tubular steel cradle, beneath the chassis, slightly rearward of the front jacking points. My vacuum source, is below the single carburettor.

 

[lilblue1970]

No it's the way it came to me. Discs on the front without servo and drums on the back. It's a 1970 so could be one of the first crossover jobs. Low lights and small rear lamps etc. Just got to say the brakes are great and will lock-up evenly front and back when stamped on, which is all you need. As I said a servo makes the braking feel lighter and slightly more efficient but in reality it doesn't improve performance because you are only still relying on what's reacting with your braking surfaces be it discs, pads, drums or shoes. Not trying to put you off the job if you feel the braking is a bit heavy, but I'd spend the time and money elsewhere. It's never going to feel like a new fangled braking system with all the shite that can go wrong with them.

 

[r73]

No it's the way it came to me. Discs on the front without servo and drums on the back. It's a 1970 so could be one of the first crossover jobs. Low lights and small rear lamps etc. Just got to say the brakes are great and will lock-up evenly front and back when stamped on, which is all you need. As I said a servo makes the braking feel lighter and slightly more efficient but in reality it doesn't improve performance because you are only still relying on what's reacting with your braking surfaces be it discs, pads, drums or shoes. Not trying to put you off the job if you feel the braking is a bit heavy, but I'd spend the time and money elsewhere. It's never going to feel like a new fangled braking system with all the shite that can go wrong with them.

Ta mate, take you got narrow 5 wheels then? I might stick the late bay discs ive got on then and see how they are before thinking about a servo. I'll have to run adapters to keep the wide 5's or change the rear set up for late model and just use the narrows.

 

[Trikky2]

No it's the way it came to me. Discs on the front without servo and drums on the back. It's a 1970 so could be one of the first crossover jobs. Low lights and small rear lamps etc. Just got to say the brakes are great and will lock-up evenly front and back when stamped on, which is all you need. As I said a servo makes the braking feel lighter and slightly more efficient but in reality it doesn't improve performance because you are only still relying on what's reacting with your braking surfaces be it discs, pads, drums or shoes. Not trying to put you off the job if you feel the braking is a bit heavy, but I'd spend the time and money elsewhere. It's never going to feel like a new fangled braking system with all the shite that can go wrong with them.

I always took the same view in the past. The bay always stopped just fine without a servo. Then one day, about 5 years or more ago, I was heading south on the motorway in Italy, doing around 70-75mph, just as it was getting dark.

The camper was well laden with four people and luggage, the road was dry, visibility was good. As I crested a brow I was suddenly confronted by stationary traffic, due to an accident. With the van moving at this speed and with a load on board I was horrified to find it was impossible to stop quickley, (let alone lock up) however hard I stamped on the pedal. Fortunately the outside lane was clear for about 10 car lengths, so I was able to swerve across for the extra braking distance needed. It was blind luck there was nobody in the lane next to me.

Up until that time I had always thought the un servoed brakes perfectly adequate. This was a horrifying moment and a major wake up call for me.

Later that year I fitted a servo, taken from a scrap deluxe microbus. It was straightforward. The hardest part was welding the mounting bracket between the torsion tubes since its position is critical - there is not much room to play with.

My first test drive was a revelation. The vehicle was transformed and the brakes felt like those of a much more recent vehicle. So I am a convert and would now never go back to un-servoed brakes on a bay.

 

[r73]

Scary moment trikky2 - was this with drums or discs? And bearing this in mind, my question 'drums with servo or discs without?' I guess discs with servo is the obvious answer

 

[cunning plan]

Not so sure about the point of view for skipping putting a servo on and spending the money elsewhere instead :? Yes, I also agree that you can have the biggest and best servo in the world, but it won't make much difference if your brakes are rubbish / badly adjusted in the first place.

So, the key here is to make sure they are as good as they can be, then to further improve, fit a servo!

I remember a few times coming up to a round-a-bout, not very fast, but having to stand on the brake-peddle, so much so, I was actually out of my seat - this is not safe, reduces the control you have of the vehicle and makes driving the bus far less pleasurable. Now, if you can increase the force on your brakes so you do not have to put all of your effort into just holding the peddle down, you can instead at least try to steer around obstacles and have a better chance of reaching the brake's maximum stopping power to the point where they lock up.

There is no way a fully loaded bus with warm brakes will lock up from 40/50mph, which means you are no where near the top of the potential braking effort. (Yes, locking up is also bad, but at least you can then back off the brake knowing that you have the maximum force down rather than standing on the brake peddle with both feet showing no real effect).

Of course, ideally, you would servo your bus AND put a disc brake conversion on the front to make them much better.

In my opinion:

Drums all round = bad
Drums back, discs front = better
Drums all round + servo = even better
Drums back, discs front + servo = Best

 

[r73]

Not so sure about the point of view for skipping putting a servo on and spending the money elsewhere instead :? Yes, I also agree that you can have the biggest and best servo in the world, but it won't make much difference if your brakes are rubbish / badly adjusted in the first place.

So, the key here is to make sure they are as good as they can be, then to further improve, fit a servo!

I remember a few times coming up to a round-a-bout, not very fast, but having to stand on the brake-peddle, so much so, I was actually out of my seat - this is not safe, reduces the control you have of the vehicle and makes driving the bus far less pleasurable. Now, if you can increase the force on your brakes so you do not have to put all of your effort into just holding the peddle down, you can instead at least try to steer around obstacles and have a better chance of reaching the brake's maximum stopping power to the point where they lock up.

There is no way a fully loaded bus with warm brakes will lock up from 40/50mph, which means you are no where near the top of the potential braking effort. (Yes, locking up is also bad, but at least you can then back off the brake knowing that you have the maximum force down rather than standing on the brake peddle with both feet showing no real effect).

Of course, ideally, you would servo your bus AND put a disc brake conversion on the front to make them much better.

In my opinion:

Drums all round = bad
Drums back, discs front = better
Drums all round + servo = even better
Drums back, discs front + servo = Best

Great summary - thanks

 

[ZedBed]

I've driven some god awful discs/no servo buses. Quite like the drums myself apart from having to adjust them from time to time, but no great shakes.

Also driven some servo/drums all round buses that would stop on a pin.

If I was looking for an upgrade I'd head for a servo upgrade - quite easy to fit in a day if you can souce a bracket. Remember, the bracket goes on at a slight angle to aim for the brake pedal - I see a few that have been welded on straight - they still work as there is flexibilty for the brake rod/servo "direction", but can't be good in the long run.

 

[raveboy]

Excellent host of responses guys (and gals ?) - I think I have concluded that i will service all of the drum
units all round replacing old worn out stuff, then adjust and get bedded in, and finaly fit a remote dual
servo. I think this will be good as I don't wish to be standing up on the brake and levering off the steering
wheel like Cunning said in an emergency stop situation.
I was also considering wether I would need to replace the master brake cylinder as well as it's the original
- Or can you buy rebuild kits for them ?

Man I'm all excited now about having brake confidence :mrgreen: :mrgreen:

Cheers all
Raver arty0046:

 

[Trikky2]

Scary moment trikky2 - was this with drums or discs? And bearing this in mind, my question 'drums with servo or discs without?' I guess discs with servo is the obvious answer

This was on my trusty old 71 bay which came standard with discs front, drums back and no servo.

Fine when only lightly laden and not going fast but, as Cunning Plan posted, simply not enough when fast and laden.

As for your question, Discs are better than drums since they suffer less from fade when hot and are less affected by moisture.

I have driven a drum braked early which had an aftermarket servo and it was pretty good.

Hence, if you cannot afford discs and a servo, then I would prefer drums and servo over discs and no servo.

 

[naskeet]

No it's the way it came to me. Discs on the front without servo and drums on the back. It's a 1970 so could be one of the first crossover jobs. Low lights and small rear lamps etc. Just got to say the brakes are great and will lock-up evenly front and back when stamped on, which is all you need. As I said a servo makes the braking feel lighter and slightly more efficient but in reality it doesn't improve performance because you are only still relying on what's reacting with your braking surfaces be it discs, pads, drums or shoes. Not trying to put you off the job if you feel the braking is a bit heavy, but I'd spend the time and money elsewhere. It's never going to feel like a new fangled braking system with all the shite that can go wrong with them.

I always took the same view in the past. The bay always stopped just fine without a servo. Then one day, about 5 years or more ago, I was heading south on the motorway in Italy, doing around 70-75mph, just as it was getting dark.

The camper was well laden with four people and luggage, the road was dry, visibility was good. As I crested a brow I was suddenly confronted by stationary traffic, due to an accident. With the van moving at this speed and with a load on board I was horrified to find it was impossible to stop quickley, (let alone lock up) however hard I stamped on the pedal. Fortunately the outside lane was clear for about 10 car lengths, so I was able to swerve across for the extra braking distance needed. It was blind luck there was nobody in the lane next to me.

Up until that time I had always thought the un servoed brakes perfectly adequate. This was a horrifying moment and a major wake up call for me.

Later that year I fitted a servo, taken from a scrap deluxe microbus. It was straightforward. The hardest part was welding the mounting bracket between the torsion tubes since its position is critical - there is not much room to play with.

My first test drive was a revelation. The vehicle was transformed and the brakes felt like those of a much more recent vehicle. So I am a convert and would now never go back to un-servoed brakes on a bay.

Retro-fitting vacuum servo assistance in 1988/89, to my family's 1973 VW "1600" Type 2 Westfalia Continental campervan, has certainly made driving more relaxing, now that we don't have to strain our leg muscles when using the brakes, whereas before, I almost felt the need to use both feet on the brake pedal, on those few occasions when emergency braking was required.

So far, there have been no problems with the braking system, nor any need to top-up the silicone brake fluid, which whilst the van has been layed-up these past several years (for further modification and refurbishment), will have protected the steel hydraulic components from rusting, which very likely would have occurred, had the system been filled with water absorbent, polyglycol brake fluid.