Dual 7" Servo - Page 24

oaktree11 · #**461** 29th January 2012, 19:18

Goo, now that IS a top tip! Actually I used a spare drill chuck to hold the bolt in but i didnt think of actually spinning it in a drill, thanks, mkII will follow tomorrow. John

Grey V8 Pete · #**462** 1st February 2012, 21:08

Despite a whole succession of unscheduled events lately that have impinged on this project I have finally fitted the dual servo unit, and very smart it looks too! For anyone else who also has the older (straight) pedal box I can confirm that the packing washers are still required to offset the servo inwards. There is approximately 6mm total pack on each of the two outer studs. This still provides minimal clearance with the bonnet side panel junction which will need a bit of careful fettling to make it all clear. I have made a neat seal around the pedal box-to-bulkhead using black silicone sealant. I finally tracked this down at Screwfix (Cat No 90574). I have also made up a cover plate for the two access holes under the pedal box as none existed before and would have let engine bay fumes into the interior :-(

I have noticed that as there are two diaphragms (and presumably two separate in-line push rods) there is more pedal travel before the front actuating plunger starts to move, compared with the old Metro one. I have also made a new bracket to raise my remote fluid reservoir another 12mm higher to retain sufficient head above the front piston.
Peter.

oaktree11 · #**463** 1st February 2012, 21:16

Peter,

Hmmmm.I dont have the bodywork yet and i Thought when I completed the trial fitment that it looks a bit close to the edge!

I was not aware that this had been an issue in the past or about the packing washers. Have you any pics?

If necessary it wont be a problem to do, I guess that it only changes the line of action of the pushrod minimally?

John

Grey V8 Pete · #**464** 1st February 2012, 21:35

Quote:

Originally Posted by oaktree11

Peter,

Hmmmm.I dont have the bodywork yet and i Thought when I completed the trial fitment that it looks a bit close to the edge!

I was not aware that this had been an issue in the past or about the packing washers. Have you any pics?

If necessary it wont be a problem to do, I guess that it only changes the line of action of the pushrod minimally?

John

Hi John. I don't have any meaningful pics of the washers and it is now all covered up by the silicone sealant. However the washers should only be needed with an old style pedal box which has a front face parallel to the bulkhead. I understand from Mike that the later ones had the front face at an angle, so the packing washers are theoretically no longer required. With the washers in place on my servo mounting, the push rod lines up with the original assymetric pedal bolt like Marlin built it. This means that my new clevis is still all on one side of the pedal (with a spacer fitted between the legs to prevent them squeezing together). In the future I would like to make an offset link as illustrated in an earlier forum post. Regarding alignment of the push rod I guess that my clevis would have fitted either side of the pedal if it hadn't been neccessary to offset the servo to clear the bonnet edge. Peter.

oaktree11 · #**465** 2nd February 2012, 07:10

Peter,

Thanks very much for the information. Its a bit difficult to judge without the bodywork in place. Its snowing right now and the garage is freezing but I will venture out there soon and take a photo looking down to see what you all think.

Its a fairly crude linkage system and if it needs angling I dont think it would be a problem.
John

Mike · #**466** 2nd February 2012, 09:33

Quote:

Originally Posted by Grey V8 Pete

I have noticed that as there are two diaphragms (and presumably two separate in-line push rods) there is more pedal travel before the front actuating plunger starts to move, compared with the old Metro one.
Peter.

Peter
You are right.
I have a spare servo left over, and have just checked that the rear pushrod has to be actuated around 2mm before the front one begins to push against the M/C.
Mike

Mike · #**467** 2nd February 2012, 09:38

Quote:

Originally Posted by oaktree11

Peter,

Thanks very much for the information. Its a bit difficult to judge without the bodywork in place. Its snowing right now and the garage is freezing but I will venture out there soon and take a photo looking down to see what you all think.

Its a fairly crude linkage system and if it needs angling I dont think it would be a problem.
John

Hi John

The entire system can be sub assembled in the warmth of your house. So you can check out the angles of the servo/pushrod/clevis in the kitchen to ensure it all line s up.
Then you'll have to brave the snow to test the clearance to the bonnet side wall. But this should not be a problem if you have the angled pedal box, as shown below by Peterux.
Mike
PS. I posted the M/C to remote elbows today.

GreatOldOne · #**468** 3rd February 2012, 16:13

I can report that the new servo also works in arctic conditions!

Just got back from a blast. Local temp approx -5, with windchill around -blooodyhellfirethatsfudgincold

Mike · #**469** 5th February 2012, 22:04

Andrew Curtis called me this afternoon, on a real high, to say how thrilled he is with the new Dual 7" servo in his BMW Sportster set up. He is another person who says it has "transformed" his car.

Whilst Andrew's call echoed GOO's comments, and those of Alan Hogg, the difference this time is that Andrew has access to a disused airfield behind his farm, so he has been out and conducted some "semi-scientific" tests. The results were quite startling.

Travelling at a constant 70mph, he braked at a fixed marker point, and measured the travel distance before coming to a complete stop.
The average stopping distance of the 4 tests with the original Metro servo was 210 feet, braking as hard as he could.

Under the same conditions with the new Dual 7" servo the average distance was 103 feet, without having to try as hard.

Out of interest Andrew then tried to brake as though in an emergency, standing on the brakes: the front wheels could be made to lock upand the stopping distance was 85 feet.
This latter test was a one off though as he did not care to waste his tyres, but felt he knew now there was a point at which the wheels would lock up at the front.

Not only is he thrilled with the improvement in stopping distance, but with the 'feel' that he now has too. He feels he can brake hard in control without excessive pressure. The emrgency stop required significant effort, and he did not happen without knowing that he was braking very hard. In an absolute emergency it was possible to make the brakes slow the car to its maximum if required.

These are the first empirical tests which actually put numbers to the improvement we anticipated for the benefits of changing the Metro servo for the Dual 7" servo.

Andrew has fitted the Ford 22mm master cylinder, with standard BMW brake components, and piped it up as per his original set up, with only two outlets being used: one to the rear, and on to the front.

He was so pleased he wanted to tell everyone how good it is!! And to thank everyone involved in bringing the project about.

I am obviously pleased for Andrew, and it confirms what GOO has experienced is now being repeated by others, both in the Ford and BMW set ups.

It is interesting he made the oft repeated decision to buy a new Metro servo as he felt his old one must have been under performing! How manyof us have gone round that circle?

For the rest of us with cars still to be put on the road, and who will never experience the limitations of the Metro servo performance, I think this shows it has been a very worthwhile upgrade: and at a very reasonable cost.
Many thanks to all who have been involved and offered encouragement or joined the project to help make it happen.

Hopefully this brings the quest for better brakes to an end.

Mike

NigelB · #**470** 5th February 2012, 22:19

Quote:

Originally Posted by Mike

For the rest of us with cars still to be put on the road, and who will never experience the limitations of the Metro servo performance, I think this shows it has been a very worthwhile upgrade: and at a very reasonable cost.
Many thanks to all who have been involved and offered encouragement or joined the project to help make it happen.

Hopefully this brings the quest for better brakes to an end.

Mike

And not without a great deal of time and effort from you Mike as well. Not only the ordering and shipment of the servos but also the design and fabrication of the adaptor plate. Many, many thanks. It's greatly appreciated. But I hope I never have the occasion to truly benefit from all your efforts..........

peterux · #**471** 5th February 2012, 22:31

Quote:

Originally Posted by Mike

Travelling at a constant 70mph, he braked at a fixed marker point, and measured the travel distance before coming to a complete stop.
The average stopping distance of the 4 tests with the original Metro servo was 210 feet, braking as hard as he could.

Under the same conditions with the new Dual 7" servo the average distance was 103 feet, without having to try as hard.

Mike

That is quite a remarkable result and clearly makes these cars much safer to drive.
I can't wait to try mine out with my new engine, as well. I'm currently overhauling my front suspension and will then move on to the brake servo.

thanks again, Peter

Patrick · #**472** 6th February 2012, 11:35

Thats excellent feedback. Did anyone find a good source for the 22mm master cylinder and/or part number.

peterux · #**473** 6th February 2012, 13:36

BMC4052 from Brakes International.

Total price was £57.96 inc. VAT and courier delivery.

Thanks to Robin for finding www.brakesint.co.uk

PLEASE READ POST #525 below before ordering this M/C. THIS PART NUMBER MAY ONLY BE SUITABLE FOR CARS WITH DRUMS AT THE BACK

MartinClan · #**474** 6th February 2012, 15:03

I bought one from there as well. Very prompt service and it was new new not some old stock that has being lying arround for ages. Fitting starts this weekend....

Robin

Mike · #**475** 6th February 2012, 16:36

Quote:

Originally Posted by MartinClan

I bought one from there as well. Very prompt service and it was new new not some old stock that has being lying arround for ages. Fitting starts this weekend....

Robin

Hey Robin

How about a before and after comparison for your set up? ..........On a deserted road of course!

Mike

denniswpearce · #**476** 6th February 2012, 19:21

Started my servo conversion today. But not quite finished.

To start with I found it extremly difficult to remove the bottom two nuts from the rear of the metro servo ( pedal box side ), you have to be a contortionist to get in there.
It proved impossible from the inside due to all the metalwork that gets in the way, so a quick trip to Halfords to buy a few appropriate tools, but then got home and discovered by running my hands around the engine side of the pedal box that the bottom of my pedal box is not sealed and I could access the two nuts with ease. Obviously the bulkhead is not sealed. Is everybody,s like that ?

Having then removed the servo it was a question of replacing the operating end of the new servo ( m/c side ) with an M6 bolt duly turned down to size and length to match up with the M/C. The new clevis pin fitted a dream and was adjusted to the right length so that all holes lined up on the pedal side.
Incidently my M/C has the markings A3 2 on the side of it and they are the only markings, so don,t know what make it is.

Obviously I removed the side panel of the car to make access easier and then loosely fitted the whole affair together to then discover that the copper pipe closest to the end would have touched the side panel. Therefore the solution was to turn the servo through 90 degrees clockwise ( as viewed from the front ). The vacuum pipe is now on the bottom not on the top as shown in all previous pics. This has the benefit now of keeping the copper pipe clear of the side. I have a remote reservoir so not an issue to which way the m/c is facing.

Unfortunately the rubber pipes from the remote reservoir are now too short but I wanted to try the new installation out so removed the remote reservoir and temporarily attached it to the servo ( tied it with string ) just so that I could bleed the brakes and try to see if it all worked. This I did and pedal pressure feels good but alas I was not prepared to road test it at night with this temp installation.
I will source some new pipes this week and hopefully finish the job at the end of the week, obviously will need bleeding again of course.

I will then take some pics so you can see the finished installation.

So thanks for everybodys input to this thread to make life easier, but if you guys do not have the bottom of your pedal box open ( from the engine side ), how the hell do you get the bottom two nuts off from inside ?

peterux · #**477** 6th February 2012, 20:12

Quote:

Originally Posted by denniswpearce

....... discovered by running my hands around the engine side of the pedal box that the bottom of my pedal box is not sealed and I could access the two nuts with ease. Obviously the bulkhead is not sealed. Is everybody,s like that ?

Hi Dennis,

yes, mine is completely open at the bottom.
I used to worry about the wind rushing in but in practice it doesn't.

I think at times Mark's little design quirks are quite clever, just not always immediately obvious

morris · #**478** 6th February 2012, 20:46

That hole in the bottom of the pedal box is what I'm hoping will keep my feet warm as I'm not fitting a heater

In fact a small electric fan may go down there to draw nice warm air in from the exhaust manifold

Not sure what the IVA man would have to say about open access to the engine bay so may seal it up just for that

GreatOldOne · #**479** 6th February 2012, 20:52

Hi Dennis,

My pedal box is open on the underside as well, but I made up a small closure plate:

http://www.greatoldone.co.uk/blog/20...kets-then.html

denniswpearce · #**480** 6th February 2012, 20:55

Not sure if the IVA man would even notice the hole. But you do get warm air blowing through so nice in winter but not desireable in summer.

Took it out a couple of weeks ago when it was cold so was welcome then. It has a heater but have never used it.

The right clothes makes a big difference. Having done a lot of flying in an open cockpit you soon get to know what clothes to wear, including headgear of course