Javelin and Jupiter Brakes

[Forumadmin]

I was so appalled by the state of some Le Mans 50th Anniversary traveller's brakes that I thought I would add this entry into the technical section to start it off.

Click on the thumbnail image to see it full size.

I have included the Girling service bulletins for Javelin hydro-mech, hydro and Jupiter. Study them carefully and then look at my checklist.

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1. Make sure there is no play in the drum through bad bearings or a worn axle shaft. I have had to either file the flange on the rear axle or fit an oversize washer so as to clamp the hub tightly onto the taper.



2. Make sure there are no oil or grease leaks through the axle seals. I use non Melting grease Admax B3 from Duckhams but you need to remove all the old grease first. Like all seals make sure the surface they run on is not worn or scratched.



3. Check all brake cylinders are not leaking. If the inside of the brake backing plate is not free from fluid, oil or grease you have a problem. The shoes should not be black, or worse, oily.



4. Check each wheel in turn to make sure the cylinders operate both shoes evenly by taking the drum off and having an assistant slowly operate the brake pedal. Do not let either cylinder move more than 0.5cm as it may move the seal onto an unused and hence rough area (and so damage it) or worse it will pop out. You might go cross eyed checking this!



5. Check you have the black, yellow and green springs and that they are in the correct holes and are not stretched or broken. Refer to the diagrams.

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6. Check you have the shoes fitted the correct way round (not upside down or inside out) The adjusting posts should meet the adjusters at some point! The shoes are leading and trailing so check they react to the normal forward rotation of the wheel. Unless you want good reverse braking! See Fig 4,5 and 6 of the Hydraulic Wedge Brake. I will let you think about it. Note that I mark all my shoes and the spares with where they are fitted and which springs go in which holes. In this way spare shoes can be fitted faultlessly on a rally. Note I always bed the shoes and the spares in before a rally.

7. Check the shoes are positioned correctly on the pistons. Of course, use brake grease in all the appropriate places. It is a good idea to take off and clean the adjuster and rear brake cylinder which should just slide and not be clamped to the backing plate.

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8. Make sure the master cylinder pivots freely. A gap of 1/32" between the clevis pin and the end of the pull slot should be maintained. This equates to about 1cm play on the foot brake. Otherwise the master cylinder will not return properly and you will end up with no brakes.This has happened at least twice before to me. I also put an extra return spring on the cylinder plunger as well as the return spring on the foot brake. Faulty outer seals may also cause this issue as they grab on the actuating rod. Hence the second spring which does not rely on the internal spring to return the rod.

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9. If fitting a master cylinder kit, make sure the rubber is the correct size even if it says so on the box!
The hydro mech has 3/4" and full hydro has 3/8" outer seal .
There is one type of outer seal which is thinner and is higher in the centre around the rod. It actually worked but the steel washer needed to be countersunk one side to ensure it did not press on the higher centre and jamb the rod. This type probably has a white plastic spreader.
There is one type of recuperating seal that looks the same but is not as tight a fit, and needless to say fails very soon. Some of these were supplied by JCC.
Some NZ kits contained a white plastic, rather than aluminium, sleeve which fails after a period of use.
Some shims have been supplied that were flat and did not have the dimples as in the original.

Pay close attention to the assembly notes on PAGE 11. The square section spacing must be present in hydro mech systems and not in full hydro.

10. I use Silicon fluid and have done for ten years (now 30 since this was written 20 years ago!) in rallying and racing, no problems , I do not have to change the cylinders every year.

11. My shoes are riveted and glued having seen problems with both separately. They are also competition linings which are not available now and not really suitable for normal driving as they need to be hot.

12. Oh yes and fit a microswitch for the brake lights. I used one on the floor board for years but picked up some new original-type at an auto jumble so have those now. I have seen the fluid pressure type used also.

13. I fitted a fluid warning sensor to the reservoir. May save pounds and a life. If you do not check EVERY time you use the car.

14. I had a new copper brake line burst on the Javelin. I think it was badly manufactured tube. OK I do have a servo fitted but?*!

[Forumadmin]

Please note that various suppliers ( including JCC and JCCNZ) have supplied incorrect master cylinder service kit components in the past which may still be around or have been fitted to cars. Such incorrect brake parts may have also been supplied by others or may be circulating in the market. JowettTalk is littered with such bad experiences.
Such parts include the outer seal, seal spreader, recuperating seal, sleeve and shim for the master cylinder. Other suppliers have supplied poorly made parts such as the MC piston, slave cylinders and brake shoes.
Identifying such faulty parts may not be easy and some do not fail immediately. If you do not rebuild or replace yourself then you need to make sure the person who does is aware of these issues.

I am trying to make it clearer how to identify such faulty components and offer solutions.
As information is confirmed I will post here.

[Forumadmin]

Neil

There is one type of outer seal which is thinner and is higher in the centre around the rod. It actually worked but the steel washer needed to be countersunk one side to ensure it did not press on the higher centre and jamb the rod. This type probably has a white plastic spreader.

Scott

comparing the shape of the ID of the seal. The original had a sharp edge and the NZ one a square profile and a fatter profile. I used a correct lip seal with the Nylon spreader and still had the same problem with the rod getting stuck.

So the chamfered washer mod needs to be done if using the NZ outer seal.

Probably not a good idea to use the white plastic spreader in place of the black rubber one.

One on left I think is original. The next is NZ which is thinner with white spreader.
The next has a seal which dishes out a bit and the rightmost is from the MEV kit.

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See another comparison from this recent post.
viewtopic.php?p=46630#p46630

There are circular rather than the original square sealing rings around. Probably are OK but watch out for leaks from the casing.

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There are white plastic, rather than the original aluminium, sleeves around which may have contributed to failure after a couple of thousand miles.

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[Forumadmin]

Came across this sleeve drawing.
viewtopic.php?p=46630#p46630

[Forumadmin]

viewtopic.php?p=22174#p22174
viewtopic.php?p=22606#p22606

[Forumadmin]

This was a query I put to Neil in 2015 when he started replacing the stock of M/C kits for NZ. At this time he also remanufactured 200 pistons and sleeves.
So I rebuilt my seven spare M/C s just after that when I received these new kits with the pistons and plastic sleeves, but I had built about 3 M/Cs using kits from NZ in 2009 so these are probably the ones in the Jav and SC.

The NZ kit supplied in 2009 contained.

1387 H1498 1 Boot Cylinder Dust Boot with tie wrap

1381 H1015 1 Seal-Outer
1383 H1483 1 Spreader Seal

1376 H2587 1 Plunger Rod as one part with-
1375 H-2586 1 Plunger Outer Shell

1379 H1016 1 Seal-Recuperating

1373 H2715 1 Sleeve




I have reorganised the parts list below in assembly order and was wondering which parts are available.

I need some of :

1384 H1736 1 Spring Seal Spreader

1390 H-2794 1 Seal Support Washer

1374 H-2504 1 Shim

Do you use silcone or some o-ring to replace

1386 H1017 1 Sealing Ring ?




ASSEMBLY ORDER OF MASTER CYLINDER
1370 54166 1 Master Cylinder H2713

1387 H1498 1 Boot Cylinder Body
1388 H1497 1 Locknut Plunger
1381 H1015 1 Seal-Outer
1383 H1483 1 Spreader Seal
1382 H1480 1 Spreader Washer
1384 H1736 1 Spring Seal Spreader
1385 H1737 1 Spring Retainer
1389 H1925 1 Washer
1378 H1735 1 Spring Plunger Return

Following two are supplied as one part
1376 H2587 1 Plunger Rod
1375 H-2586 1 Plunger Outer Shell

1390 H-2794 1 Seal Support Washer
1379 H1016 1 Seal-Recuperating
1374 H-2504 1 Shim
1373 H2715 1 Sleeve
1386 H1017 1 Sealing Ring


1354 50457 I Compensator Clevis Pin
1355 50424 1 Master Cylinder Fork Nut
1356 50423 1 Master Cylinder Rod Fork
1362 54071 1 Master Cylinder Rod
1363 FN105/K 2 Nut, Master Cylinder Rod
1353 54072 1 Master Cylinder Adaptor

1371 H-2714 1 Cylinder Body-Front Half
1372 H-1817 1 Cylinder Body - Rear Half
1377 H1927 3 Setscrew Cylinder Assembly
1380 40-S-32 3 Spring Washer, 5/16 in. dia

1363 FN105/K 1 Nut, Master Cylinder Eye bolt
1357 54073 1 Master Cylinder Eye Bolt

[Forumadmin]

The brake failure at Goodwood in 2012.
viewtopic.php?p=14093#p14093
Now was this caused by a 2009 NZ kit?

The brake failure in 2010.
viewtopic.php?p=10711&hilit=master+cylinder#p10711
Now was this caused by a 2009 NZ kit?

Problem after rebuild.
viewtopic.php?p=1058#p1058

Please note other problems have been experienced with parts from other suppliers.

[PJGD]

I remember Ben Shaw telling the story of the occasion that he had brake failure in his Javelin one day on the way into work. His normal route to the BBC Outside Broadcast office in Park Royal, West London was down the A40 which back then in the 1960's was all surface streets with many roundabouts at the major junctions. Ben normally drove quite enthusiastically, and on this occasion he approached one of the roundabouts at speed, applied the brakes, and the pedal went to the floor. There was no way that he could get around the roundabout and so he had to go straight on over it. Fortunately, the bushes on the center island slowed him down and he managed to stop before coming out of the far side. He was in such a state of shock that he had to just sit there and smoke a cigarette to calm down. While sitting there, a police car pulled up and the constable said to him "You know you can't park here!

The post mortem on the brake failure was that the aluminium collar/shim in the master cylinder had split.

[Keith Clements]

Ben Shaw's experience was in the same car as Scott's, XMG258! Just 60 years and 500000 miles earlier.

[Mike Allfrey]

"The postmortem on the brake failure was that the aluminium collar/shim in the master cylinder had split."

Hey Philip,

Thank you for relating Ben Shaw's experience.

Now, I wonder, did the aluminium collar or the shim split? I have never seen a split collar (sleeve), but did find a broken shim in my Jupiter's master cylinder. It had broken to form a spring washer style, and there was no drama at the brakes - the pedal feel was good, just a bit too much travel before it felt solid. The cause of that was found to be a deeper bore in the rear body of the master cylinder.

I fitted a new shim that was supplied by Neil in NZ. Works fine now.

Regards,

Mike A.

[PJGD]

Mike: Ben related that story 50 years ago now over a pint of beer. I think that perhaps it was the shim that split in his case.

[Mike Allfrey]

Hi Philip,

Ah! The pint of 'best' bitter!

I am, after some thought, assuming that the shim broke in such a way that pieces may have damaged the recuperating seal, otherwise it is difficult to understand why the brake pedal went to the floor.

The split shim from the Jupiter may still be in my workshop, will have a look and take a photo.

Regards,

Mike A.

[Keith Clements]

Noticed a leak around the body of the mc on Amy's SC so will be investigating that soon. Maybe shaft seal or body seal ( is it square or round section)

[Mike Allfrey]

Hi Keith,

Had a look in my workshop, but could not find the split shim. Attached is a photo of the NZ supplied shim, I have not tried bending it, but it feels quite springy. Note that the dimples alternate from side to side. One of these is in the Jupiter now.

Pulled apart an hydro-mechanical master cylinder recently, it showed evidence of leakage at the outer seal. Discovered that the seal was a piece of hose - brake or fuel, not known. What some people do!
Regards,

Mike A.

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[Nick Webster]

Mike,

I have just had a look at a genuine Girling overhaul kit and the shim looks identical to the one in your picture. It is tinned steel. Must take some effort to split it.

Nick