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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MG Y Type - Jackall threads

Does anyone know the thread that is used on the screws that fasten the copper pipes to the jackall pump and rams.There are two ODs 1/2" and 7/16" and the thread has 24 tpi at 55 degrees. The nearest I can find is BSB which has 26 tpi. Even better a supplyer of the 7/16" screws.
Peter

Peter Vielvoye

Dear Peter

Thank you for your enquiry. The answer is that they are actually all British Standard Pipe (BSP) fittings. I think you will find the answer is located on the IMGYTR site at http://www.mg-cars.org.uk/imgytr/technical.shtml#Threads.

Please let me know if you still need further details and we will be happy to assist.

Paul
Paul Barrow

Peter,
Try asking Roger at Mad Metrics, I'm certain he would assist you.

Richard
R E Knight

Peter

You should be able to get BSP fittings from any good plumbers' merchant in the UK as they are still used on gas and water systems. I have had no difficulty in the past.

Mike Long
M Long

Thanks gents but would be interested to know where your BSP information comes from. A 1/4 BSP has an OD 13.157 which is just over 1/2" and has 19 tpi. The fittings in my picture are definitely 24G TPI so a 1/4BSP will not fit. The 7/16" OD fitting does not even have a BSP equivalent. Tried phoning Roger at Mad metrics but not available.
Peter
Peter Vielvoye

David Pelham Peter.
Paul Barrow

Peter,

Try emailing Roger ... roger.46tc at gmail.com replace the at with @

Hope Roger can help you.

Richard
R E Knight

I can confirm that the threads are not BSP. I have contacted Roger and my bit of research has gone full circle. An engineer working for SVW Spares to develop jackall spares contacted the Y Reg a while back as we have some origial drawings of the jackall system (which are on our site). So I got back to him when I needed two of these screws and he said they were having trouble with the screw threads. I decided to do a bit of research myself and as you know eventually emailed Roger. He says he has been asked to make some Jackall fittings for SVW and confirms they are 24 tpi BSB. which is none standard. Why they should be is still a mystery. Will post the outcome.
Peter
Peter Vielvoye

Peter
I have a copy of Molesworth Handbook of Engineering Data dated 1951. It includes thread details for numerous types of bolt and threads, but I can find nothing even close to your description. It does not appear to be a standard thread in use at the time. We know that Morris Motors used obsolete French threads in their engines, for historical reasons, but the Jackall system was not made by Morris - bought in from an outside supplier. Sorry, but I can offer no more suggestions.
Mike
M Long

I have run across this which explains BSB gut they are not 24 tpi

BRITISH STANDARD BRASS

BRASS THREADS (British Standard Brass)
Because brass tubing has a uniform wall thickness, irrespective of the tube diameter, any thread cut on, (or in) it, would
have to have the same depth, so 26 tpi is standard on all diameters. An example would be the thread cut on the brass
trumpet horns of the 30s cars, although many were die-cast rather than brass. If it were 1" O/D, the thread would be 1"
Brass, 26tpi.


BSB has a 26 TPI pitch through the whole range and is often confused with BS Cycle thread the difference being that brass thread has an angle of 55 degrees whereas Cycle is 60 degrees. Brass threads are usually confined to fittings and adjusters on cables.
Brass thread taps and dies are sold and advertised as 26 tpi and are identified by the letters BSB.


Jim B
JA Benjamin

Perhaps this is a better series although 60 degrees.

BSC (British Standard Cycle) Thread Data

This fine thread profile was formulated for, and is well suited to cycle and motorcycle applications. Its fine pitch, allows high torque settings, and resists the tendancy to loosen under vibration, the larger core diameter also gives greater shear strength. Most people think that all cycle threads are 26 tpi pitch. Whilst this is true of all the most popular sizes from 1/4" to 3/4" diameter, other pitches were also used as shown in the tables seen in the CEI section

We have numerous taps and dies in BSC with 20 tpi threads.

Angle of thread = 60o


Jim B.

PS. chart comes from;
BRITISH TOOLS & FASTENERS, LLC
7696 ROUTE 31, LYONS NY 14489
sales@britishfasteners.com
TEL- 315 946 9400 FAX - 315 946 9344

JA Benjamin

Thanks Jim
The BSB thead with 26 tpi has been tried but tightens after a few turns. It is the nearest standard thread we could find. The photo shows a 55 degree whitworth thread gauge fitting perfectly on to our screw. As you see it is 24G, not sure what the fractions refer to. Sorry its a bit small.
Peter

Peter Vielvoye

Peter
I have just refurbished the Jackall system on Y4162 and I did replace the feed pipe from the reservoir to the distributer pump as it leaked and the olives were shot, I made up a brand new pipe with new brass fittings and I can confirm that the 5/16 dia. pip fittings are"Brass Pipe fitting male 1/2" X 24 UNF, long for a 5/16 pipe" I got mine from automec.co.uk not cheap £7.04 delivered for 2. I assume the 1/4 feed pipe will be the same standard but I have not measured them, I went through the same routine with the 26 vs 24 tpi. Mike
M R Brown

Thanks Mike
I have now taken delivery of the Brass 7/16 x 24 unf fittings from Automec. The !/2 x 24 unf for 1/4 pipe are still unavailable.
Peter
Peter Vielvoye

Hi Guys,
I am also currently doing some repairs on our YTs Jackall system in particular the pump which has been leaking it seems from every orifice! I have purchased a seal set from the MGCC Y Register but it does not come with the rear seal for the shaft. I took the old seal to a hydraulic specialist to get a replacement and thought I should share the outcome for future reference if it has not been recorded before. The only markings on the seal are USA, VBG-4 and .562. The only meaningful number is .562 (9/16 in Decimal inches) which is the shaft Dia. There is no makers name or part number as such however the sales docket refers to it as an Energised U seal 18700562. This number is an international code for seals I believe referred to as the Parker method? Measuring across the seal wall width is .187 (3/16" decimal inches) and .562 is the shaft as mentioned above. Therefore twice the wall thickness = .374 + .562 = .936 (15/16")which is the bore of the pump body. How easy was that? Finally when the seal body is virtual square there is no measurement for the seal depth, if it were narrower or deeper that measurement number would be at the end of the string not in the middle! One more, it only cost AUD10 + Tax!
Cheers
Richo YT3208
R A Prior

Hi Richo et al,

If anyone has difficulty in getting these seals let me know since this one is marked USA it may well be USA made (???). I have a supplier here locally that has sourced unique bearings for an MG SA before now that were not otherwise available elsewhere in the world for a UK owner so is well used to my crazy requests!!

Paul
Paul Barrow

Richo et al

Me again. Just spoke with my guy at Harbor Hydraulics here in Grays Harbor and he is getting me a price for 18700562 and will be coming back to me today. I plan on buying at least dozen from him so I will be able to supply these for you all.

Paul
Paul Barrow

Paul thank you for sourcing the rear shaft seal for me following my unsuccessful attempt to purchase some in the UK.
C P Callaghan

Paul.

Can I request 4 please, as they are available I'll purchase some whilst I can.

Another superb effort sourcing spares and parts, where would owners be without, Octagon, IMGYTR and commercial boys such NTG. Sign of good club is the quality of parts it supplies to its members using small number of owners to make up economies of scale and venture worth while to reproduce obsolete items. We now need shock absorbers repaired, too long with vintage shock absorbers Croydon, I've been waiting well over two years, wait goes on.and also decent head gaskets too be useful.
R E Knight

XPAG Head Gaskets in modern materials - superb quality, are available in Australia, but they are not cheap.

You get what you pay for here.

Cheers

Tony
A L SLATTERY

Hi Paul,
If it helps with the numbers to get a price deal, I'll have two or more from you, to put on the shelf.
Keith
Keith D Herkes

Tony,
I concur you get what you pay for. I got an old Payen banana shape gasket for £70 something which was great as it contributed in solving my overheating problems in YT. My issue at the time was a cheaper option from an MG club that supplies parts looked inferior and I felt it would be a possible weakness, though I never fitted it, so cannot for fact say I would have had a problem. A chap for double the cost made one to pattern by hand which was top quality. In my mind if it works and can sit on shelf until needed it's worth it.
What cost are the ones in Australia out of interest? Without wishing to bring in politics, but I do hope the price of goods to/from USA and Australia will fall as new trade agreements are agreed as a result of Brexit. I don't see many quality parts made in EU for Y Type, unlike Australia and USA.
Richard
R E Knight

Hi Guys,
A couple of more comments. I had to go shopping for some 5/16 olives today, not a problem living in a mining town like Perth, I got some from Pirtek just down the road a bit! I showed him the 24 TPI nut but no joy, he did suggest to retap the hole to 20 TPI? (I think) which would then be a standard fitting. However whilst on the net I discovered a UK supplier that has them in various tube sizes, 1/2 thread 24tpi for 5/16 tube is CA165 and only 2quid ea. https://www.completeautomobilist.com/categories/complete-automobilist-fuel-system-taps-pipe-and-fittings-fittings. You may also know them as Vintage Supplies Ltd.
10G Folgate Road
North Walsham
Norfolk
NR28 0AJ

Do any of you know this supplier? Maybe there is a local Y Owner who could pop in and see if this item is what we are chasing?
Cheers
Richo
R A Prior

OK back to the pump shaft seal. The 18700562 is a modern lip seal not a donut seal which is probably what was originally used. There is a minor complication with this type of seal in this application that needs to go on the record (Paul). You cannot fit the seal into the pump body first then insert the shaft because the shaft will be pushing against the internal lip of the seal. If you do manage to force the shaft through then next the lip will snagg on the cotter pin groove and surely be damaged. The best approach is first insert the shaft then with some lubrication on the shaft ease the seal, lip first of course, over the shaft. With the seal in the cotter pin groove very carefully slide the seal forward and ease the lip over the inner edge of the cotter pin groove. The seal can then be slid forward up to the pump housing. However, because the outer lip is protruding it does require some patience to gradually and carefully work around the seal with your thumbnail to get the seal into the housing. A little trick here to avoid frustration is to get a nicely symmetrical (Round) Jubilee clip and close it around the seal just enough to compress the lip. Line it up over the hole and hey presto push it into the hole just like a piston ring compressor!!!
Cheers
Richo YT3208
R A Prior

Richo

They say a picture is worth 1000 words so any chance you can email me some pictures so we can make up some comprehensive instructions? I am receiving the initial delivery of 12 seals soon.

Thanks

Paul
Paul Barrow

Hi Paul,
I have taken some shots of fitting the seal so I will rewrite the fitting instructions and send it all over in an email. I am going to be away for a few days so it will have to wait until my return.
Cheers
Richo
R A Prior

Sounds good.

Paul
Paul Barrow


I also had bought a seal set from the MGCC Y Register, with the one seal missing.

I had the seal made to order by a Swiss hydraulic shop using modern HPU material. The size being 5.3x14.2x6mm deep (14.2 mm equals 9/16"). At about 40.- £ the seal was not cheap, but at least it does a good job.

To fit the seal over the shaft, I made use of an old trick of the trade, using a rolled up peace of thin steel shim to protect the seal while sliding it in position. See picture

Cheers
Anton Piller, Y/T 4220

Anton Piller


By the way, it helps to make up a rigg to service and test the pump. See picture.

Anton Piller, Switzerland

Anton Piller

Anton,
Could you clarify a couple of points for me please. I am pretty ignorant about all this!

1. What exactly is HPU?
2. Is the seal that you had made a lipped seal or a copy of the ‘donut’ type original. It sounds from your use of the shim that it might have had a lip.
3. If it is a more modern type ‘lipped’ seal, was there a reason why you didn’t get your supplier to make a pattern to create a reproduction of the original seal in a modern material (whatever that might be)?
Best wishes, Mike.
YT/EXR 2744
Mike Silk

Mike

HPU is a Thermoplastic Polyurethane (water resistant) material that is suitable for use in high pressure hydraulic sealing applications. The material is extremely wear and extrusion resistant. It is highly resistant to oil swell, ozone, oxidation and abrasion, it also has excellent cut resistance. Highly resilient, urethanes also have high tensile strength and elongation properties. Urethanes remain an excellent choice in hydraulic systems using petroleum based fluids. Most urethane seals remain flexible and efficient in temperatures ranging from -65° F to +200° F with some able to withstand intermittent temperatures up to +300° F. HPU is the abbreviation for hydrolysis-resistant polyurethane.

Paul
Paul Barrow

Thank you, Paul

There is nothing to add to your comment :o)

Greetings
Anton
Anton Piller

Reactivating from the archives but scroll down to the last few photos:I was just looking at Anton Piller's excellent 2017 photos of his beautifully refurbished Jackall pump.
In a moment of madness today I decided to start stripping mine - and this horrible mess is what I found! No doubt this is typical. I've had the luxury of visiting Neil Wakeman in Melbourne (3,000kms away, but it's "what you do"), and learning first-hand about his well documented method of cracking open the ram tubes.So I'll put together a few photos of the strip-and-refurb of my pump, in case it helps anyone. John.


J P Hall

This thread was discussed between 28/03/2017 and 24/02/2020

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