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Volvo Servo Upgrade


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4 hours ago, JochemsTR said:

Volvo 960-940-740-760 with 8" diameter and 2 membranes.

if mounted onto a RHD, you need to check my adapter. it probably needs mirroring.

Cut a piece of wood and make a template out of my drawing. Take a piece of cardboard and make a 8" volume. Believe it or not, this is how I did it.

Jochem

And a part no for the brake master cylinder Jochem. Will the original Triumph master cylinder fit? 

What is the dimensions of the servo including the master cylinder in length?

As you can see I am keen to try this.

Regards Harry

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36 minutes ago, harrytr5 said:

And a part no for the brake master cylinder Jochem. Will the original Triumph master cylinder fit? 

What is the dimensions of the servo including the master cylinder in length?

Yes, the original master will fit. The whole thing will shift about 2" forward, so you need to extend or redo some of the brake lines. For a LHD it was the lines from the PDWA to the Master which are just a few inches. Not sure RHD.

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15 hours ago, ntc said:

So what’s the gain over original?

Higher ratio servo assistance, most moderns have a lot more assistance than original fitment on 5/6.

Stuart.

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50 minutes ago, ntc said:

Never had any problems with std can lock all four wheels if needed and so can the daughter 

I`m the same, if all the rest of the system is up to snuff then the brakes are very good. I dont even have a servo on my 4a and I can lock up all 4 without too hard a push on the pedal.

Stuart.

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Hi Stuart and Neil,

the lower vacuum on PI cars influences the servo effectiveness, off course. On my US-spec TR6 I never felt the need for a larger servo. But that was many moons ago, I got older, traffic much busier, and now I have a PI.

The standard brakes met the MOT requirements, but with the Volvo servo I can break easier/faster.

Cheers,

Waldi 

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24 minutes ago, Waldi said:

Hi Stuart and Neil,

the lower vacuum on PI cars influences the servo effectiveness, off course. On my US-spec TR6 I never felt the need for a larger servo. But that was many moons ago, I got older, traffic much busier, and now I have a PI.

The standard brakes met the MOT requirements, but with the Volvo servo I can break easier/faster.

Cheers,

Waldi 

I get to drive PI cars a lot, and dont really find them any different in the assistance and I know Neils cars are mostly PI too, I do know that wild cams give lower vacuum

Stuart.

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Hi Stuart,

I think it also depends on the drivers choice and in my case, physical condition.
Each to it’s own as they say.

Cheers,
Waldi

 

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12 hours ago, Waldi said:

Hi Stuart,

I think it also depends on the drivers choice and in my case, physical condition.
Each to it’s own as they say.

Cheers,
Waldi

 

Of course, a customer of mine needed a servo on his clutch due to loss of left leg strength.

Stuart.

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On 9/9/2021 at 9:12 PM, Steves_TR6 said:

I like your setup Gavin

could you let me have the part numbers as i might try something similar !

steve

Apologies for the slow response gents, been away for a few days.

I've attached some images which will hopefully be of help to those who my want to do the same.  The pump is Hella unit probably common to many VAG models, my son thinks it was a Q7, but it was a couple of years back and we knew what we were looking for when we went to Pick a Part so didn't take too much notice.  It's mounted in an accessory alloy fuel pump bracket on a fabricated steel tee fastened to existing bolts on the firewall.  The controller is a small adjustable vacuum switch I purchased off eBay from memory, used for controlling older auto transmissions as I mentioned.

At the moment all vacuum is from the pump, but at some point I will also connect the original manifold connection with a check valve to act as a backup.  The engine pulls 10" of vacuum at idle and I have the pump set to 13" with the ability to dial in even more if I want.  Works well as it is though.

Hope this helps :)

Gavin

 

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  • 2 weeks later...
On 9/11/2021 at 9:37 AM, stuart said:

Of course, a customer of mine needed a servo on his clutch due to loss of left leg strength.

Stuart.

I have a similar issue and would love to hear more about the clutch servo . I have been planning to use the Racterrations thrust bearing mod but a servo may be less hassle and cost.

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1 hour ago, Tony M said:

I have a similar issue and would love to hear more about the clutch servo . I have been planning to use the Racterrations thrust bearing mod but a servo may be less hassle and cost.

Its basically another brake servo fitted on the opposite side of the engine compartment and plumed into the clutch hydraulic line and "T" into the brake servo vacuum line as well.

Stuart.

 

Tonys TR6 624 - Copy.JPG

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20 minutes ago, Tony M said:

Hi Thanks for that. And does it feel really light now and give good control?

That was quite a few years ago but yes it really helped, the servos are available in different ratios so you can make it very light indeed.

Stuart.

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  • 3 weeks later...

I can confirm it fits on a UK car. Well, when I say it fits, you will need to "relieve" the inner wheel arch at the bottom of the servo by about 4mm. That equates to about 3 light taps with a copper hammer with a cloth wrapped around it. The inner wing has about 3mm clearance with  no work required.

The clevis on the end of the servo is a little wider and you will need a new clevis pin maybe 5mm longer if you don't want to squash the clevis in a vice before fitting. The brake pipes don't absolutely need extending if you add a 1" standoff at the last place they are clamped by the clutch cylinder mounting plate just to lift them a little.

 

The adaptor plate is pretty much as Jochem's drawing but you don't need the offset in the holes as the clutch master cylinder is not in the way on a UK car.

 

 

IMG_1694.jpeg

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  • 2 weeks later...

Tony,

 

no, not been on the road yet as I finished it then had to go abroad on business but will hopefully find time this week. The servo is for Volvo 940 08/94 > also fits 960 from 08/94 to late 98 and S60 V90.

https://www.ebay.co.uk/itm/OEM-VOLVO-V90-MK1-BRAKE-BOOSTER-9157699-GENUINE-/283809445298

If you google using search terms   9157699 booster Volvo     you will find loads of them at various prices. Mine came from Germany and cost £137 to my door.

 

As a little update you don't need to "adjust" the bottom of the inner wing if you use bolts from inside the car to fix it rather than studs from the mounting plate and nuts inside. That occurred to me after I had finished, as the best ideas always do!

 

I didn't photograph the plate but it is pretty much as Jochems drawing except that you don't need to offset the inner and outer holes from each other as the servo can stay dead centre on the RHD car as the clutch master doesn't get in the way. You can also use a full four holes for the servo and four for the mount to the bulkhead because losing the offset means that there's meat for the drilling all the holes. The inner square and outer squares of holes are quite close so marking out accurately is important. Using the old servo mount plate as a template for the bulkhead holes makes this part easier. Also make the recesses for the servo nuts as small as possible to just get the nuts in plus a thin wall socket, this gives plenty of room for the threaded holes for mounting to the bulkhead and don't use the nuts that come with the servo for this purpose as they have a return on the bottom making them much wider than necessary which makes the required precision even more critical. I think the whole job took me maybe 4 hours from a slab of aluminium and Jochems drawing to a completed job. Tools needed:

A bandsaw (saves a lot of sweat with a hacksaw) but not absolutely needed, especially if you get the plate cut to order.

A pillar drill will certainly be better for getting good straight and perpendicular holes through the thick plate

6.8mm drill bit for the M8 tapped holes for the bulkhead bolts

M8x1.25 tap, tap carefully to get a good clean thread, plenty of backing off and cleaning out as you go. Use thread lock on the through bulkhead studs (or bolts).

8.3mm drill bit for the servo mounting studs

a decent centre-punch to get all the holes right without the drill squirming around as you want them all within tight tolerances.

a 12 (ish) mm bit for making the recesses for the servo nuts to sit flush in the aluminium. 13mm is pushing your luck so own judgement and measurement advised.

a hole saw and arbor to make the hole for the rod to go through the plate. I think it was 57MM but check as my memory isn't the best.

a swearbox whilst getting the old servo bolts out whilst upside-down in the drivers footwell.

 

 

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Hi Jon. Many thanks for such a helpful and detailed response. It has definitely inspired me to carry out this mod. Its surprising to see such variation in price for the servo! Did you keep the same thickness for the plate of 20.9 mm? I seem to be able to buy 20mm cut to size and hoped this would do. I'm going to remove my servo and check the mountings.

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17 hours ago, Tony M said:

Hi Jon. Many thanks for such a helpful and detailed response. It has definitely inspired me to carry out this mod. Its surprising to see such variation in price for the servo! Did you keep the same thickness for the plate of 20.9 mm? I seem to be able to buy 20mm cut to size and hoped this would do. I'm going to remove my servo and check the mountings.

I used 20mm. In fact 25mm might be better BUT you may find a problem with clearance between the top of the reservoir on the bottom of the bonnet. With the 20 it was close but I used a bit of plasticine about 5mm thick on the reservoir cap as a test and it didn't touch. We all know the tolerances that 1970's BL cars were made to so a 25mm block might be pushing your luck a little.

20mm leaves the brake peddle about 1" higher than the clutch but of course that can be easily dealt with by shortening or maybe adjusting the servo threaded rod by a few MM. I have not yet tweaked that as I want to drive it first before I judge if or how much I adjust it. At the moment it's raining and roads are covered in mud so my garage queen is not coming out.

 

Edited by FatJon
correction
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