Dual 7" Servo

[timbo]

I will be interested once I get the car back from the 'expert' in Caerphilly.........
Tim

[Grey V8 Pete]

Hi Jason / Mike. Just a thought about the adaptor plate thickness. From the dim and distant past I seem to remember that a thread should locate in a plate / nut etc for a thickness no less than the thread diameter. With 8mm studs holding the master cylinder that would indicate that the adaptor plate should be 8mm thick and not 6mm. With MBM quoting 1000psi line pressure needed for a disc brake set up that’s a lot of force being held by those two studs :-o What do you think? Pete

[Mike]

Originally Posted by Grey V8 Pete

Hi Jason / Mike. Just a thought about the adaptor plate thickness. From the dim and distant past I seem to remember that a thread should locate in a plate / nut etc for a thickness no less than the thread diameter. With 8mm studs holding the master cylinder that would indicate that the adaptor plate should be 8mm thick and not 6mm. With MBM quoting 1000psi line pressure needed for a disc brake set up that’s a lot of force being held by those two studs :-o What do you think? Pete

Peter

Adaptor Plate
The intention for the universal plate was for you to drill a hole and counter sink from the back. Then fit the adaptor to the master cylinder, using a counter sunk socket screw. Then bolt the adaptor to the servo.

I plan to weld 2 x m8 studs in my adaptor, and can get the same done for anyone who can advise the exact position of the studs. ie centres, and angle of rotation from vertical.

I have been to see the guy who makes these today, and will get a trial one made first to ensure all the dimensions are spot on (as he will cut them out on a laser cutter), so any mistake will be repeated. The final quality will be very good.
I can then post photos of this, with a note on the critical dimensions if there is a requirement for welded in stud connectors.

Dual Servo Update
I have chased Paul at Duksville today, and he is not prepared to give us a price until he can get his next delivery, and knows his landed costs. To be fair, this fluctuates due to the $/£ exchange rate, and his price for the one I bought does not leave him much of a margin. He can not give any indication of when he might get his next delivery.

It is not in my nature to be fobbed off, so I have contacted MBM brake boosters in Ashville NC. They are willing to sell us 18 or 24 off (they come in packs of 6) at $50 each, after negotiating. I am waiting for a price for 24 delivered to me direct. If I have done my sums right, even at this price we can't get them for the price Duksville were selling them at, taking in to account freight, Import duties, and VAT. My best guess would be around a cost of £80 each delivered in bulk to one location. If my sums are right and everyone remains happy at this cost, we will be able to get them before Christmas.

Whilst many of us do not need to rush to buy one of these servos during the close season and may feel waiting might get a better price, Duksville will not guarantee the next batch will be at the same price. I have offered to place an order today for 20 off at the last advertised price, but he will not accept it until he knows his costs. It could be more, it could be less..........?

I will let you know as soon as I hear anything from from MBM.

[Grey V8 Pete]

Mike. All noted thanks. I’m up for paying a bit more to get the servo asap rather than wait and hope for a better price that may never happen.

Re the long clevis: I appear to have the offset Marlin connector at present, see pic. Is the intention to still leave the offset set up when using the threaded long clevis, albeit with some packing washers between the legs? Peter.

[GreatOldOne]

I also had the offset adaptor for the metro clevis.

I didn't reuse it with the new one - I just have the pedal through the middle of the long forks of the clevis, with the pin securing it. You just need add a split pin through a hole thats predrilled at the end of the pin to stop it from working out.

Mike - I also don't mind paying a little more if it secures an a definite order.

[peterux]

Originally Posted by GreatOldOne

I also had the offset adaptor for the metro clevis.

I didn't reuse it with the new one - I just have the pedal through the middle of the long forks of the clevis, with the pin securing it. You just need add a split pin through a hole thats predrilled at the end of the pin to stop it from working out.

Doesn't that put the servo pushrod at the wrong angle?
To keep the original pedal box geometry, it might be better to use a short clevis and the original adaptor? (Although I know Mike hates the adaptor )

BTW...I'm surprised Dukesville aren't more keen for an order for 20 servo's and not willing to take orders at the current advertised price?

[Mike]

Originally Posted by Grey V8 Pete

Mike. All noted thanks. I’m up for paying a bit more to get the servo asap rather than wait and hope for a better price that may never happen.

Re the long clevis: I appear to have the offset Marlin connector at present, see pic. Is the intention to still leave the offset set up when using the threaded long clevis, albeit with some packing washers between the legs? Peter.

Peter

The Dual servo and long clevis has significantly improved the design over the poor engineering solution adopted by Marlin.

It has three big advantages:

The long clevis connects the brake pedal and the servo directly eliminating the dubious centre pivot arrangement your photo shows - see Tim's earlier thread response about an actual failure of this Marlin design.

The yoke of the clevis will sit each side of the brake pedal, giving a much stronger engineering connection, and ensuring the force of the pedal is directed through the centre line of the clevis and is better aligned to the servo.

The adjustable nature of the threaded clevis will also allow fine tuning of the final height of your brake pedal to suit individual preference.

In short - it is a proper engineering solution.

[Mike]

Originally Posted by peterux

Doesn't that put the servo pushrod at the wrong angle?
To keep the original pedal box geometry, it might be better to use a short clevis and the original adaptor? (Although I know Mike hates the adaptor )

BTW...I'm surprised Dukesville aren't more keen for an order for 20 servo's and not willing to take orders at the current advertised price?

Peter (ux)

That is an interesting point. I have a Cabrio, not Sportster, though I suspect the Marlin pedal box is common in both. I seem to remember the offset arrangement was just as Peter (Grey V8) suggests - offset.
I re-made my brake pedal to give greater clearance between brake pedal and accelerator, so it was not standard, and I specifically designed it for my clevis to attach either side of a new dummy brake pedal which was set to be directly in-line with the servo.

I also supported both the clutch and accelerator pedals on both sides, eliminating both cantilever arrangements. Both are much more solid as a result.





I also welded an extended clevis to my servo to eliminated the Marlin arrangement
(Peterux is right - I think it is crap!)



The clevis should be attached either side of the pedal though. It is poor engineering practice to cantilever loads when they can be supported on both sides. It will ensure the load is pushed through the centre of the clevis.

I spent over half an hour on the phone to Paul at Ducksville, and I was left with exactly the same impression as yourself, Peter. He made a comment to the effect that he makes Hot rods that sell for £40-50k, so an order like this is just chicken feed to him.
To be fair though I suspect he does not add a big margin, so he won't take the risk on the exchange rate changing against him. That's when I decided to try to go direct to a manufacturer.

I shall pursue this some more later this week, though I'm open to any helpful suggestions! I may have to upset Goo and get him to take the new Dual servo out to weigh it. MBM suggested as an off the cuff comment that the servo weighed around 10lbs. I used this to get UPS to calculate the (air) freight cost. I have weighed the Metro one since, and it only weighs around 3.3 lbs. I know the Dual felt significantly heavier, but 3 times as heavy?
It may affect the calculation for freight if it is appreciably less than 10lbs?

Does anyone have any experience of international freight? MBM suggested the only way is air freight? It's obviously quick, but as Rob Martin said, "Eye wateringly expensive".

[MartinClan]

Jason - please put me down for a clevis as well. As for the price I am OK as long as the total doesn't go much above the £80 mentioned.

On the Marlin supplied pushrod extender - I had a slot milled in mine to fit the brake pedal and then moved the brake pedal over by a few mm to line up. (Ground a few mm of the mounting bush one and side and thick washers the other.) It means that the force you apply on the pedal goes directly to the push rod. Brakes are still crap though....





Robin

[GreatOldOne]

Originally Posted by peterux

Doesn't that put the servo pushrod at the wrong angle?

Not that I've noticed.

Originally Posted by Mike

I may have to upset Goo and get him to take the new Dual servo out to weigh it.

NOOOOOOOOOOOOOOOOOOOOOOO!



Just let me know when you want to pick it up. I doubt Vikki will be venturing out much now until next year.

[Sorton]

Just to complicate the ordering/buying/shipping process, I - and I suspect others in a similar situation - have put my name on the list but am in no hurry to take delivery. I do not need express service as I am months (years!!!) from needing the servo.

Sorton

[peterux]

Originally Posted by MartinClan

On the Marlin supplied pushrod extender - I had a slot milled in mine to fit the brake pedal and then moved the brake pedal over by a few mm to line up. (Ground a few mm of the mounting bush one and side and thick washers the other.) It means that the force you apply on the pedal goes directly to the push rod. Brakes are still crap though....




Robin

Thanks, Robin, that looks like the mod we need to get the full force directly in line with the servo pushrod.
I'm not looking forward to crawling back into the drivers footwell to get it all out again.

Maybe Jason can offer a fitting service as he must be getting good at it now?

[denniswpearce]

Yeh, practice makes perfect.

I am sure we could all offer him 50p per car, he will be the countries leading expert after modifying all ours.

What an accolade " The best in the country at Marlin Brake mods "

Go for it Jason

[GreatOldOne]

50p? Wow. I'll quit my day job and do it full time.

[Mike]

Guys - It's decision Time.

I've had the following response response from MBM,

Hello Mike

Thank you for your inquiry. Your shipping charges would be about $850.00 USD for 4 cases of 7" dual boosters (24). I do have the stainless steel available, but it is considerably more expensive and still sold by the case. Here is what I can do for pricing...

· PB7537 $50.00 (Plain zinc 7” dual booster)

· PB7537PC $75 (Black powder coated 7” dual booster)

· PB7537SS $140 (Stainless Steel Booster)

All of these boosters are high quality and vacuum tested before leaving our facility, but I want to caution you regarding any potential warranty claims that because of the cost associated with shipping these across the water and the fact that we are giving you a wholesale price without being a dealer for us, our warranty would not be extended in this case. If this arrangement is satisfactory to you and you’d like to move forward with an order, please send me your order via reply email with the follow information.

· Name

· Address

· Telephone number

· Method of payment

· Parts you’d like to order and quantities




Sincerely,



Steve Brown
End Quote.




I searched a price from UPS's website of £480 for freight, which is not wildly dissimilar to MBM's $850 - so for the difference of £2-3 per unit I'd rather they organise freight.

So we are in a position to place an order for those that want to fully commit - no wish washy responses Sorton!

MBM's stainless unit is 3 times the price of the zinc, and we have to order in cases of 6, so I unless 6 of you come forward, we will reject that.
Are there 6 takers for the powder coat black?

MBM will not offer a guarantee to us in the UK due to the high cost of shipping to UK - does this deter anyone?
If you are quick there are 4 off Dual 7" servos on ebay for £90 and I'm sure they will offer a guarantee!..... Loyalty? .......What's that?..........

I believe that with the current exchange rate, VAT, and Import duties the zinc servos will have a landed cost of £75 - £80 max - assuming we get charged VAT at 20% of the MBM landed price.

The adaptor will be £7, or £10, depending on preference, and the clevis £3 each.
Ducksville charged me £9 for delivery, so I trust £10 will cover including the adaptor plate and clevis.

So how many are fully committed to an order this week, at a cost for the complete kit at around £100 delivered?
I could bring them to Stoneleigh next year for those not in a rush and wanting to save £10!

We will have to order in cases of 6 - so I'd like to get 18 or 24 hands up.

I am happy to order several spare adaptor plates, and don't mind holding a few as stock, but do not want surplus servos hanging around at £80 each.

I feel I have done all I can now, and would prefer to place an order early next week to avoid the Christmas rush if the commitment is still there?

Over to you.........................?


Regards
Mike

[Patrick]

Fully committed will opt for powder coat if there are not 6 stainless people. If not enough for powder coat then zinc (+clevis + adapter (in stainless))

Funds ready to be tranfered via bank transfer or PayPal gift.

[morris]

count me in for plain zinc coated + clevis + adapter

[peterux]

Hi Mike,
great work (we all owe you a beer or two, or maybe a hand with your electrics?)
Count me in for a zinc Servo, steel adaptor plate and clevis.

Like Patrick, I no longer have a cheque book, so bank transfer or Paypal preferred.

thanks

Peter

[GreatOldOne]

Ready to order here. Still would like stainless, but I'll go the same route as Patrick and have a powder coated one if there isn't enough demand for the stainless. Paypal or BT - your choice.

[NigelB]

Mike,
Count me in for the lot.
And many thanks for all the efforts you have put in over the last couple of weeks to the benefit of us all. Great job.
Nigel