NEW FULL-HYDRAULIC WHEEL CYLINDERS

[David Morris]

Hi All,

Thanks for the excellent comments. Having been involved over many years with safety-critical systems, I can only add that we cannot take short cuts with our single-circuit brake systems on Javelins and Jupiters. Jowett's wouldn't be allowed to sell them today!

My advice is never buy NOS brake components, like master cylinders, cylinder seal kits or hoses, you never know how old they are and they perish with time. With solid hydraulic pipes, I managed to purchase some years ago an excellent Sykes Pickavant Brake Flare Tool, that would do several types of flares for the ends of the pipes and is intended to be clamped in a vice. They are not cheap, but accurate. Perhaps JCS have one of these or could purchase one that could be loaned via their tool loan scheme? You would only need to borrow this once in a while? Finally, as I have mentioned before, fit a 'tell-tale' visual extension to the fluid tank under the bonnet, for peace of mind every time you open the bonnet.

One other point, I had a total brake failure on my Javelin on the way to the Crieff Rally, which was caused by the lossening of the shaft that holds the brake and clutch pedal pivots. It's just something that you need to check for security when underneath the car! Fortunately, the long bolt that acts as the shaft hadn't fallen out and just needed tightening into the captive nut. But the brake pedal went to the floor just before and that was not a good feeling in the middle of Edinburgh's rush hour traffic! Do check yours!

All the best,

David

[Mike Allfrey]

Good Evening All,

Further to what I have written on this topic, here is added information:

1. The L.H.S. rear wheel cylinder had been sleeved with stainless steel. It leaked fluid onto the brake shoes three times.

2. Part of the problem with the County cylinders (rear) was the air excluder spring being longer than the original(?) Girling spring.

3. The County air excluders have longer spigots for the spring - meaning that they contact each other before the brake shoe webs make contact with the handbrake tappets, not at all good.

4. The County AR-55 L or R rear wheel cylinders as supplied from Jowett Car Spares, have exactly the same marking for an Austin-Healey model, but are three times the price of those from JCS. I know that A-H folk are wealthy types, but . . . .

5. Keith Clements is due to arrive here on 9th April, I have a completely revised set of my Technical Notes Series, There is one Note devoted to the County saga. That should be issued with every County cylinder sold.

I trust that the matter is now mostly resolved.

Cheers,

Mike A.

[Forumadmin]

The discussion can be followed here and is a complimentary to this topic.
viewtopic.php?p=48521#p48521

I was going to move the relevant posts into this topic but have left them there.

I found some time today after fixing an intermittent petrol pump on Amy's Jup to look at my selection of brake cylinders.

I think the pump issue was a loose connection caused by the plastic nut that locks the feed wire so I replaced with a 2BA washer and nut. It may have been the pitted points so I cleaned them up with a sharpening stone.
Or it way have been a broken/breaking wire, so I replaced that with some multi core wire.
Tested by pumping a gallon into the spare can.

So I compared what I think was an original rear brake assembly with the County recently purchased from JCS and the set of stainless steel sleeved cylinders and pistons I purchased in NZ.

Immediately you notice the difference in size of the NZ piston which is for the front cylinder. The rears are the same as original later slotted type.

Notice the different parts numbers on the castings.
The top is County.
The middle is a Girling replacement fitted to a Jup long ago with slotted piston.
The bottom casting is for the original flat piston with metal cap rather than rubber boot.

The NZ stainless steel sleeved pistons fit into the 412820 castings which have been stainless steel sleeved, but you then fit the rubber boot on the piston.

Secondly, when compressed in the vice, the County retract to the same point as the original metal cap slaves.

This is what happens if silicone fluid is not used.

I will get around to posting the updated technical notes from Mike, but is quite a big job checking and making sure any previous references into the old notes are not lost.

[Forumadmin]

I thought linking to an earlier post in this topic would help see what started this discussion. It clearly summarises the issues which need to be considered.

viewtopic.php?p=47502#p47502

[Mike Allfrey]

Thanks Keith,

I have a feeling that the pistons for the front wheel cylinders are of different length from those fitted in the rear wheel cylinders. Should that be so, even further care should be taken during selection.

The data I have indicates that the fronts and rears are the same diameter, but there is no mention of length.

Mike A.

[Keith Clements]

The newer slotted rear pistons are 23.47 mm into slot and the older flat piston with metal cap are 25.56mm.

The front old are 18.94 plus 1.5 mm for the cap =20.44mm and newer slotted are. 20.54mm into slot.

[Chris Spencer]

I write amazed the Keith & Mike are still on the same bandwagon hyping on about this subject whilst demonising the excellent service provided by the team at Jowett Car Spares - Just to reiterate that JCS are not responding because of the way that you have gone about this saga in the first place with your knee jerk reaction attitudes in taking to social media first to bang your drum rather than what you should have done in the first instance and raised your concerns directly with JCS - I'll stand firmly with them in the respect that I'll probably purchase more brake parts from JCS than any other individual - In turn these are fitted to my clients / fellow members Jowetts - none of which have any issues along with all other members that are purchasing the same brake parts - The pair of you ought to be ashamed of your actions.

[Keith Clements]

Chris, Please do not make this personal. There is no intention of critiscising the service volunteers provide but Mike and I think it is important to make other members aware of issues with brake components available on the market, not just from JCS. See below the response received from Paul Beaumont to the email sent by Mike on 16th May 2023.

Hi Paul and Keith,

A question, has anyone installed the same County AR55L & R rear wheel cylinders, those that have been supplied to us? If so, how have they resolved the non-operating handbrake situation?

To explain, photograph 129-007, shows a new rear wheel cylinder installed on one of the rear brake back plates. Yellow vertical arrows ‘A’ show massive clearance between the brake shoe web and the handbrake tappet face. The Photograph, 129-008, shows one of the original pistons having dimension ‘C’ measuring 0·297-in., and the same measurement taken on the new cylinder’s piston, in photograph 129-009, has the dimension of 0·230-in.

That illustrates where the clearance, 0·067-in. at each tappet comes from. That results in a total error of 0·134-in., not at all within a manufacturing tolerance range. With such clearances, the handbrake is not at all operatable, due to the draw link reaching its stop before any vehicle holding action takes place. This is not at all good.

The distance ‘B’, in photograph 129-007, between the horizontal arrows is the fully compressed length over the pistons with the brake shoes held in place with the yellow spring. This dimension was compared with the original wheel cylinder when its pistons were fully compressed. The difference in compressed lengths differed by 0·002-in., not to be worried about.

It should be noted that all of the dimensions were taken with a digital Starrett Vernier calliper. The calliper has been found to be accurate over a number of years, compared with a micrometer and feeler gauges.

There is also the concern where the brake drum may not fit over the brake shoes, due to them being held further apart.

I can see some options for deepening the slot (groove) in the pistons, however, it appears that the new pistons have been coated with an anti-friction coating, so gripping the piston for milling the slots deeper could be difficult. If such can be done, it makes the setup non-standard. Another option is to have handbrake tappets with added length. Again, such a modification would be away from standard. The third, and probably the optimum solution is to have the supplier provide pistons that can actually be installed first time of trying.

Yesterday, we spent a great amount of time trying to find screws that fitted the tappet cover plate. On my Jupiter, the left-hand side cylinder had different thread screws from those in the other cylinder, but then, that is all part of the Jowett Experience!

Please advise what action should, or will, be taken to resolve the handbrake concern.

All the best,

Mike A.

This was the response from Paul.

From: Paul Beaumont <pjabeaumont@gmail.com>
Sent: Tuesday, May 16, 2023 10:04 PM
To: michael.allfrey@bigpond.com
Subject: Re: New Rear Wheel Brake Cylinders



Mike, we are aware of this problem that manifests itself from time to time. My solution is to dismantle the cylinder and retrieve the 2 mushroom shaped mouldings that replace the seal spreaders in the original Girling cylinders. These also serve as locators for the spring between the 2 pistons. If you remove approximately 1 mm from the stem of each of these then the pistons will retract further and the problem should be resolved. I believe that the problem comes about because County have copied an aftermarket cylinder (probably Quinton Hazel) who I suspect also redesigned the shoes with the aim of making the linings last less time!!

Paul

[Chris Spencer]

Keith

Mike and I think it is important to make other members aware of issues with brake components

And there's a right way to go about this:

First thing to do is make sure that you have all the correct information to hand, contact the suppliers with your concerns and ensure that there is no further information / help available and that nothing has been lost in translation in your own assumptions

And there's a wrong way to go about it: (which in this case yourself & Mike undertook)

Adopt a 'knee jerk reaction' attitude and bleat your assumptions in a instantaneous manner on a social media platform in turn casting a dark shadow & doubt over the very helpful voluntary services provided for the clubs members through the excellent Jowett Car Spares

Chris, Please do not make this personal

Don't make me laugh - this is what you wrote about me on this very platform (05/05/2024)

please disregard what Chris has said as he has a habit of upsetting people

The word that needs to come firmly in your direction is 'Hypocrite'

Now having firmly made my points clear and not wishing for it take any more of my time yet alone that of any other members - I need to get back to my workshop and prepare several things for the national rally in a few days time - Safe travels to the members attending - catch up with you all soon

[Forumadmin]

I do not know how to put this more clearly than my last post which showed the email from Mike to Paul Beaumont and then reply from Paul, representing the supplier, JCS, on the same day the 16th May 2023 . That is over one year ago.

The first post in this thread dated 17th May 2023 was a day after Mike received the reply from the supplier, JCS, stating that Paul knew of the problem with the rear cylinders.

So I do not think it unreasonable for Mike to have started this thread then AFTER contacting the supplier and receiving a reply confirming the problem.

Since such County wheel cylinders are available from other suppliers it is very responsible of Mike to have alerted us all of the problem and to have also drawn attention to the problem in the Jupiter Restoration thread.

It is thanks to such people as Mike that club members get such a good spares service from the various club spares schemes and get sound technical advice via this forum.

Thank you Mike.

[Chris Spencer]

And in complete contradiction of my point in the first place - Mike wrote the following on 4th May 2024 @12:49 on this very forum :

I have been trying to get some form of action from Jowett Car Spares Limited on the subject of the County full hydraulic wheel cylinders not being fit for purpose. The silence from JCS has been profound.

Still banging the drum & still driving negative connotations at JCS less than 3 weeks ago - I rest my case (Although somehow I get the strong feeling that a very small minority won't)

[Keith Clements]

Chris, do you admit you got it wrong that Mike did not contact JCS first before posting on JT?

Has the problem with the County supplier to JCS been fixed such that modifications to the innards are no longer required?

How many of the inappropriate County cylinders are in circulation, not only those supplied by JCS but by others?

I think there were other emails sent by Mike to JCS on the subject which were not answered. There maybe valid reasons why this is so. Mike thought the solution proposed by Paul was not sensible. Such a mail trail is not appropriate to be published. If a problem exists then we do need to share it. So is there still a problem with these County cylinders and does it only affect specific installations?

Chris, you say you have fitted many of these County parts without issue. Did you know about the issue and check to see there was no problem? So why did Mike have an issue? Clearly from Paul's response the problem was known about before Mike contacted him. So why were those who had been supplied with the cylinders not been informed?

I am trying to act as moderator on this forum so please, Chris, can you try not to upset club members like Chad and Mike who contribute substantially to this forum. There are more diplomatic ways of making your views known.

We all support the great work the volunteers of the clubs' spares schemes do and realise that sometimes problems and priorities occur which need addressing.