Replacing Front Wheel Studs - Hydromechanical Brakes

[trymes]

Well, I was tightening the lug nuts onto my Javelin (#10010) when one felt a little strange and then snapped off. It did look as though the stud had been previously cracked and thus weakened, or perhaps I'm stronger than I think (I really wasn't putting all *THAT* much force on the ratchet).

Anyhow, it looks like I'm going to have to source a stud or two (another one felt a little odd, too) and remove the hub/drum from the car. This looks intimidating, at least never having done it before. Does anyone have any tips/tricks or information on the studs themselves? Ideally I could avoid having them shipped in from the UK (I'm in New England), but I suspect they're unique to the Javelin.

Many thanks for any insight you can provide!

Tom

[Chris Spencer]

Tom - The club run Jowett Car Spares stocks replacement studs & nuts although I'm aware that some members have sourced a stronger stud (possibly early series Land Rover) but I'm sure others will be along to confirm - You will need a hub puller to remove the drum - Jowetts have a specific puller for this but it requires removal of the bearing locking ring on the front drums - alternatively I have seen the drums removed with a wide legged puller with the bearing & locking ring left insitu - a puller of this type should be readily available in the market - Once removed its just a matter of tapping the broken stud out with a drift and reinserting the new one - image of both the Jowett specific puller which is internal thread on the front drums / external thread on the rear drums along with a 10" universal puller below - these you will find quite cheaply on e bay etc

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Scott Renner may well be able to help you out / have studs in stock - he is LA based - you can PM on the forum his user name is: Srenner

[Keith Clements]

Hi Tom,
Worth checking all studs have not stretched or cracked. Scott will have some but maybe Peter Leopold who is coming to Florida soon can bring some over.
Note many tyre fitters over tighten. Max should be 40 lbs ft not the 60 or more of modern cars. They are not high tensile.

[Srenner]

Man, forget to check JT for one day and my ears start burning.

Tom, not hard at all. Sent Robin a few some years ago and have some on hand.

Chris is correct that a large puller will work (Harbor Freight cheapy works well)and sometime wiggling with the wheel still attached also works. Back off the adjusters first, do not bother with the locking ring as the outer bearing is good to come off with the drum. Then it's hammer time! Knock the old out with a punch, line up the shoulder of the new stud with the shoulder of the liner. Nice to press new ones in, but can be done with a hammer.

Good idea to check all the studs by running a nut the length of the stud, feeling for change in how tight/loose it feels.

Drop me a PM here and I will send a phone number.

[trymes]

Thank you to all for chiming in. This all started as I didn't realize that the hub and drum are integral on these cars. The LF brake was dragging a bit, and I figured I'd pull the drum, familiarize myself with the brake components, and then refit the drum and adjust the brakes.

Once I realized the drum was integral, I instead worked to just adjust the brakes, and thought I had done a fantastic job, with just a touch of drag when rotated in the forward direction. Then, today I notice brake fluid leaking from that wheel, so apparently I left it FAR too loose in the adjustment and the cylinder blew a seal. Joy!

Oh well, now I get my chance to pull the drum, replace the stud, and inspect the brake bits.

Sent you a PM, Scott.

[David Morris]

Hi trymes,

If you have the early hydromechanical brakes, and if my memory is correct, you will not be able to use the type of Jowett puller shown in one of the posts, that fits in place of the outer bearing locking ring. This ring was only introduced for the later full hydraulic brakes, to retain the outer bearing. I think the earlier hydromechanical setup used a setscrew to retain the outer bearing.

The drum can be pulled off using a normal three-legged puller, or something similar. I made one up with some angle iron and a beefy setscrew. The drums are usually not very tight, but I recommend that you change the bearings if they are at all worn.

There was a later conversion kit introduced by the Factory to fit taper bearings to the front wheels, which would have been far more sensible. Ball races for the front wheels are not recommended, with the stresses here. Even the rear wheel bearings, which were supplied with the differential by Salisbury, were tapers and these are not subjected to the same cornering forces.

All the best,

David

[David Morris]

Hi All,

Keith's comment about overtightening wheel studs is correct. What often happens at your local tyre fitters is that when refitting the wheel to the car they grab the 'windy hammer', smack it onto the wheel nut or bolt and let it whine away at maximum torque. Then, they grab the torque wrench to check that it is sufficiently tight. Of course it's tight! Probably around 75ft lbs or more!

Then, when you have a puncture and the rain is pouring down, you cannot get the nuts off with the flimsy tools supplied with any car, modern or classic! The solution is to carry a breaker bar, with an extension and a suitable socket, in the boot of whatever car you are driving. It hasn't got to be your best bar, just one you could pick up cheaply in a car boot sale. You will bless it when the nut or wheel bolt moves!

All the best,

David

[Keith Clements]

The rear hub puller for the hydro mech is different thread to that for the full hydro. I have a puller that is fitted to the five studs and pushes on the axle so is suitable for front and back and all models. Heavy so not suitable for carrying in the car, so have separate pullers for the two models for the car toolbox.

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https://jowett.org/jowettnet/dt/tech/br ... brakes.htm

[trymes]

Thanks to everyone here for advice, and thanks to Scott for hooking me up with new wheel studs. I took everything apart today and now I have a new group of questions:

1. The axle nut was barely tight at all. Is that normal?
2. I didn't have a puller big enough to fit around the drum, but I just grabbed the edges of the drum and it pulled off with some patience and minimal force. It didn't just pull of with zero effort, but it wasn't terribly difficult, either. Is that normal?
3. Related to #1, how tight should the axle nut be when I reassemble? I've not found anything in the manual. I've also done an MGC before, where there are shims that need to be adjusted such that there's zero play when the nut is torqued down, but this does not appear to be that style. I assume I should torque it up to a specific value and then back it off by a certain amount. Any help is appreciated!
4. The pegs that adjust the shoes such that they are parallel to the drum are almost to the end of their adjustment range. It seems fine, but I'm not certain that's normal.
5. The brake adjuster goes from zero contact to almost fully locked up in a tiny amount of travel. There seems to be almost no in-between. Is that normal?

Any insight you all might be able to provide would be much appreciated. Here's a quick video I made while scratching my head at what I had found.

YouTube video - Jowett Javelin Front Brakes and Hub

Tom

[David Morris]

Hi Tom,

Thanks for the video, that's a good way to explain things.

It's a long time since I had hydro-mechanical brakes to replace, so others might have more recent experience. I am surprised that there isn't a spring to hold the back shoe in place?

I would suggest that you drive out the bearings and test them for slackness on the stub axle. They should come out quite easily with a drift on the shoulders.You might well find them to be loose on the axle, hence making the drum easy to pull off? Also, the bearings themselves might be slack and overall need replacement. I am sure JCS have spares, or your local bearing dealer?

As for the hub oil seal, I am sure this has separated into two parts, the seal plus the spring that should lie behind the seal to provide tension. In other words, the seal is junk, and should be replaced.

The hub nut should be re-torqued to the figure which I am sure should be in the manual. Unlike taper bearings, which need to be tightened to a point where the bearing just gets 'tight' and backed off a flat, these nuts should be quite tight, as it's a straight metal to metal contact right to the backplate. I guess around 30lbs ft would be the figure in the book, or around that figure, when aligning the split pin holes. Don't back it off, just go further.

Hope this helps,

David

[trymes]

Thank you, David. I can’t find anything in the manual for a torque setting. Hopefully someone else can chime in and point me to where it is.

[Forumadmin]

viewtopic.php?t=6313

[David Morris]

Hi Tony,

What I suspect has occured with your hydromechanical brakes is that the loose hub nut may give the clue. With the ball races, there should be a continious metal path from the hub nut, through the outer bearing inner, through the spacer, on through the back bearing inner, to reach the back plate. The whole lot should be reasonably tight. You found the hub nut almost hand tight, so something has been moving?

What might be the cause is that one, or both, of the ball race inners may have been turning on the axle shaft, thereby wearing their outer surfaces of the ball race centres, reducing the effective length of the assembly and hence loosening the tension on the outer nut? That is why I suggested taking the ball races out and seeing if they are worn, or perhaps loose on the shaft. Being just simple ball races, that really shouldn't be used as front wheel bearings and this means they have a fairly short life. I would consider changing them anyway, and if JCS are too far away, your local bearing stockest may be able to find ones that will fit?

The fact that the grease seal is also shot, may indicate that things were moving here. I would change the seal and the bearings and then tighten the whole lot up to a good torque. What Jowett's might call 'tight'. Not 'dead tight', by which they meant 'spanner-busting' tight!

Hope this helps,

David

[trymes]

Thanks you for the replies. I am, it turns out, nowhere near JCS, and my email to spares@jowett.org is still awaiting a reply.

I don’t have any part numbers, or I’m sure I could have a decent shot of finding the right bits locally.

[trymes]

viewtopic.php?t=6313

This is a post about the rear hubs, and I did find it and many others using the search function before posting my reply, but it seems that the front hubs are the same?