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I'm done with the brakes | Powermaster III nightmare | Partslist for conversion


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It seems to turn out we're stuck. Calipers are OK, presuming Master Cylinder failure. We'll check some other things using the workshop manual, but some day we'll stop flogging the dead horse. As I won't be able to convert the car to non-ABS in Germany due to regulatory issues and the originality will be lost, I'm tending to sell the car. 

Question: Does anyone have any idea where to either get a replacement for the Delco PMIII master cylinder assembly -OR- know somebody able to refurbish them?

Thanks!

 

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I spoke to Pete at PNM Engineering about the Delco master cylinder a couple of weeks ago. He said that he can strip and clean them, but it takes about 4 hours of labour. You could try asking him first.

As for the ABS, do they check the ABS function in Germany, or just the lamp illumination like we do in the UK?

Margate Exotics.

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On 6/5/2016 at 12:10, casewolf said:

It seems to turn out we're stuck. Calipers are OK, presuming Master Cylinder failure. We'll check some other things using the workshop manual, but some day we'll stop flogging the dead horse. As I won't be able to convert the car to non-ABS in Germany due to regulatory issues and the originality will be lost, I'm tending to sell the car. 

Question: Does anyone have any idea where to either get a replacement for the Delco PMIII master cylinder assembly -OR- know somebody able to refurbish them?

Thanks!

 

How did you inspect the calipers?  I've seen a few of the rear single piston Brembo calipers develop a crack in the piston that prevents the piston from sliding correctly. This is not easily visible without removing the dust boot and pulling out the piston.

Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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On 5.6.2016 at 21:07, ian29gte said:

I spoke to Pete at PNM Engineering about the Delco master cylinder a couple of weeks ago. He said that he can strip and clean them, but it takes about 4 hours of labour. You could try asking him first.

As for the ABS, do they check the ABS function in Germany, or just the lamp illumination like we do in the UK?

That is great to hear - could be the solution!

8 hours ago, Vulcan Grey said:

How did you inspect the calipers?  I've seen a few of the rear single piston Brembo calipers develop a crack in the piston that prevents the piston from sliding correctly. This is not easily visible without removing the dust boot and pulling out the piston.

Well, to be honest, we checked the front left caliper only, as the car is having trouble there. We detached it from the disk an checked the pistons sliding, they were doing so "normally", while I applied the brake carefully. We did that several times to see, if there is any hint of delay or tipping point, but to no avail. Anyhow: Next week the brakes will be disassembled and checked in detail. Keep fingers crossed.

But: As I made up my mind about the car - it will be sold anyhow. I cant justify that kind of trouble to me, and I lost confidence in the whole system.

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  • 2 weeks later...

While checking around last week, and it appears to me that the Delco Moraine Powermaster 111 master cylinder is now NLA, and I couldn't find any repair kits, either. That is going to be difficult if someone requires one, or even needs to rebuild one.

Which poses the question: What now? As much as I hate to change anything from standard I'm wondering if it's time to bite the bullet and convert to a vacuum servo system in the not-too-distant future, and store the original Delco kit for when I sell the car. There looks to have been a few conversions done, although from what I've read no definitive kits of parts, which is what D.C. has been after in this thread.

Does anyone know the bore size of the Delco master? I assume that would have to be a similar size.

 

Margate Exotics.

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I don't think setting up the vacuum servo system is the problem though.  I think the real dilemma is the vacuum source.  The Esprit motor is "cammed up" enough, and turbocharged aggressively enough, that I don't think it produces enough vacuum in enough situations to be relied on to provide brake assist.  Thus the obvious solution, borrowing a system from a modern turbocharged car (Subaru WRX or Ford w/eco-tech), I fear won't work simply because of our unique motor.  

 

 That would mean sourcing an external vacuum pump and reservoir system, either a big electric pump (far bigger than the toy we use to operate our heater flaps) or a motor driven pump (which I believe is what earlier Esprits used).  Or getting real inventive like the Swedes did with old turbocharged Saabs.... http://saabworld.net/showthread.php?t=675

 

The fellows who did the Esprit conversions seemed to have their early enthusiasm sour as time went on.  One mentioned the possibility of harvesting a vacuum reservoir from a wrecked car, I suspect in an attempt to make the brakes more reliable.  If I recall correctly, they were attempting to simply use engine vacuum.

 

Just my 2 cents.

 

      

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2 hours ago, Richard123 said:

I don't think setting up the vacuum servo system is the problem though.  I think the real dilemma is the vacuum source.  The Esprit motor is "cammed up" enough, and turbocharged aggressively enough, that I don't think it produces enough vacuum in enough situations to be relied on to provide brake assist.  Thus the obvious solution, borrowing a system from a modern turbocharged car (Subaru WRX or Ford w/eco-tech), I fear won't work simply because of our unique motor.  

 

 That would mean sourcing an external vacuum pump and reservoir system, either a big electric pump (far bigger than the toy we use to operate our heater flaps) or a motor driven pump (which I believe is what earlier Esprits used).  Or getting real inventive like the Swedes did with old turbocharged Saabs.... http://saabworld.net/showthread.php?t=675

 

The fellows who did the Esprit conversions seemed to have their early enthusiasm sour as time went on.  One mentioned the possibility of harvesting a vacuum reservoir from a wrecked car, I suspect in an attempt to make the brakes more reliable.  If I recall correctly, they were attempting to simply use engine vacuum.

 

Just my 2 cents.

 

      

 

No, I don't think the turbo engine will produce enough vacuum, however I don't think that's a problem. There are various vacuum systems around, my first choice would be a Hella vac pump, possibly with a reservoir/accumulator. I haven't visited Summit or Jegs the see what they've got yet, but I think sizing the master cylinder and servo correctly could be more time-consuming.

I would try to get the most up to date master and servo to stave off obsolescence, and that's when the real hunt begins. The Delco master has three outlets, although a twin outlet would suffice and split the output to the fronts. Also, it would need a level warning device to tie into the ECU. The ABS would have to be cheated as per the resistor method.

 

Margate Exotics.

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The early turbo engines were manifold fed, on the basis that the brakes are needed mostly when the throttle is closed, so there's a fair bit of vacuum on the engine side of the carbs. A smallish pump may be enough if a similar manifold feed is also in place (with non-return valve) so that the pump is only called on when there just isn't enough from the engine.The later engines that used a mechanical pump were fine (occasional pump failures and loss of belt tension) but became impractical when the space they occupied was needed for the mechanical pump for the steering. The older servos were large volume, if these modern pumps are used then I's suggest checking the volume of the servos they pair up with, so as to not increase the time necessary to have assistance in place between braking sessions, although smaller volumes may mean less assistance I doubt that's much of a problem for the cars with the larger brakes (those with 258mm may struggle).

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14 hours ago, andydclements said:

The early turbo engines were manifold fed, on the basis that the brakes are needed mostly when the throttle is closed, so there's a fair bit of vacuum on the engine side of the carbs. A smallish pump may be enough if a similar manifold feed is also in place (with non-return valve) so that the pump is only called on when there just isn't enough from the engine.The later engines that used a mechanical pump were fine (occasional pump failures and loss of belt tension) but became impractical when the space they occupied was needed for the mechanical pump for the steering. The older servos were large volume, if these modern pumps are used then I's suggest checking the volume of the servos they pair up with, so as to not increase the time necessary to have assistance in place between braking sessions, although smaller volumes may mean less assistance I doubt that's much of a problem for the cars with the larger brakes (those with 258mm may struggle).

 

 I imagine the larger the servo diaphragm diameter, the more assistance provided, but the volume behind it would dictate whether it requires a larger vacuum pump capacity to support it, or an accumulator.

Someone on here (Dave?) removed his A/C compressor to fit a vac pump, but I'm not prepared to do that, hence electric is the only option.

Margate Exotics.

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  • 1 month later...
On 5/29/2016 at 10:39, andydclements said:

When I looked at moving from mechanical to electrical vac pump I looked at the Hella ones, and felt that the volume of the Esprit servo is such that those Hella ones aren't really big enough on their own, fine until the brakes need to be applied, released and re-applied in quick succession. I've obtained one that the USA guys use when retro-fitting servos to classic trucks that didn't originally have assistance. Hella could be a good option to boost the manifold vacuum.

This is not true in regards to the Hella not being capable - see my post in the  "Calling all brake gurus" thread...I ran my S4s around and had a passenger call out vacuum levels from a gauge with a line ran into the engine compartment and it does not provide ALL the vacuum needed but it does provide some during normal cruising and almost all you need under complete throttle release - but a supplemental pump is needed for these repetitive brake applications.  These UP28 pumps are on A LOT of production cars - especially small turbo Audi 1.8 Turbos, Volvo turbos, and VW Turbos which probably produce even less vacuum than our 2.2L. They are also on GM vehicles with direct injection and ALL look the same - just some are made in Germany and some in Mexico.  A new one can be found as low as $80 shipped.

You will need a reservoir - the Audi three "ball" blue one would do fine easily found on Ebay, many turbo cars or direct injection have them so don't necessarily limit yourself to the Audi one. A larger one would give you a bigger reserve of vacuum. You'll need a vacuum switch to turn on and off the pump  (like this http://www.newark.com/multicomp/psf109s-81-330/pressure-switch-spdt-11-9psi/dp/24R7147) with a relay (suggest a Bosch 30A relay) that has adjustability for on and off setting, you'll also need a one way valve between the reservoir and the vacuum pump to maintain vacuum in the system so that it does not bleed off.  A turbo boost bleeder can be used to fine tune the amount of vacuum assist available to the booster to adjust the amount of assist..

The GT3 after 98 had a small vacuum pump (now obsolete) and appeared to be used in conjunction with manifold vacuum - so every solution would need a reservoir along with the pump...but the 2.0 likely put out a little less vacuum than the 2.2.

 

Casewolf

I have an unused PMIII unit that I purchased many years ago when I had the same problem (pulling to one side).  A complete flush of the entire system cured that problem following the factory manual procedure exactly.-including bleeding the system at the master bleed screws.  Car has been fine since for the past 8 years and I never used it and it has sat in a box since as a spare for that "one day".  It was a new one for the Pontiac Grand Prix Turbo (which was the donor vehicle Lotus used from GM). The original GM units were not exactly the same as the Lotus one -  Its sole difference is at the rear of the unit where you'd likely need to swap the machined aluminum piece where the rod from the pedal pushes at the master.  It is held in place with a C Clip which could be removed and swapped with the piece from your old unit.  If you are interested in purchasing it PM me..

 

 

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Hi DC,

When I said I fitted an earlier type vacuum pump, I didn't fit it where the steering pump is, but I removed the AC pump and fitted vacuum pump on a custom bracket in its place. There's no much need for AC here in Ireland anyway.

The problem is if you fit an electric pump is that if you loose electric power you'll loose servo brake assist.

I'm very happy with my system and wouldn't got back to the old system.......ever.

My next step is to fit a proportioning valve so I can adjust the amount of brake bias between the front and rear breaks.

Cheers

Dave

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@Casewolf, have you read this topic, scroll down. It seems that a Toyota or Subaru servo and master cylinder works, had a lot of troubles with my powermaster III, installed the new switch from Ralf Burk, a new accumulator, new pads, new brake fluid and bleed the System according to the Workshop maual two times, the car really stops now. If you need the parts (servo and master cylinder from a subaru) they are still in my garage, to try out if this workaround will give you better brakes, let me know.

Gruss Andre

 

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Hello @all!

Just wanted to come back and share my experience with you. As it turns out, the "oldest-official-Lotus-workshop" and "Esprit-specialist-garage" failed utterly. I won't drop names, but anyone in Germany knows whom I'm talking about. This is very annoying, because I lost my faith into them. Their behaviour is at the brink of cheating, but I won't say that officially, thats just my feeling about it. Without getting into much detail, I will tell you what I did.

I discovered a corrupted hose (the one, that connects the Pump/Accumulator-Assembly with the Powermaster), it was sweating brake fluid. Seems it was at the end of its lifetime, and not since yesterday! It was then replaced by me and with the help of my mechanic we flushed the system 2 times (using the workshop manual, including the bleed nipples at the Master - @Paul93Lotus ... thanks for your offer!). I think even a third or fourth time could let the brake system benefit, as the second time there was still a lot of air trapped. So I'll do it another time soon, because, additionally there is a small leakage at the cover of the powermaster that will need to be fixed by a new filler cap for the reservoir.

End of story: The car stops.

BUT:

Why hasn't anyone seen/inspected the hose before me? It was obvious (at least for a mechanic, not even a specialist)!
Why did they tell me, that the car has been flushed, when it wasn't - or at least not properly?
Why was the fluid like milk after depressurizing - and when I replaced the fluid, not?
Did they use old fluid?
Didn't they replace it?

Too many questions for me. I'm very disappointed with the service I experienced and I'd expect any mechanic to take a focussed look at parts that are obviously not working properly, the way I did (5 minutes!). Instead they just did "something" (I don't know what...?) and charged me over 1000€ in the last year just for flushing the system three times.

This car is something for people that are brave enough to fiddle around with components that have no OEM-replacement anymore. I'm not that brave. Regrettably, as much as I like the car, I think I need something I can at least order parts for... :(

Edited by casewolf
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