Ribbed brake drums

[Fraze]

Question for the Gurus : Were  FC brake drums ribbed? The drums on my FC are all ribbed and I have four spare drums (obtained from two separate sources) which are also ribbed. Or are all of these after market. I also have an FB which has ribbed drums per the FC ones (but 1/4" wider). Are these aftermarket as well? Next question - I have heard that EH drums interchange with FB - EK without mods or changes - is that fact? Thanks, Fraze

[Errol62]

Hi Fraze
Read the recent thread titled FE/FC Drums started on 1/2/17 by RET. These are Repco after market and improve cooling to reduce fade.

I wonder how common these are.

Cheers
Clay


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[Errol62]

Also recent discussion on the FB EK site


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[ardiesse]

Fraze,

All the FC drums I have seen so far have been ribbed, but that's not to say that all FC drums are ribbed.
On the other hand, FB/EK drums come in both ribbed and plain varieties.  Usually the ribbed drums ended up on the front and the plain drums on the rear if you had a vehicle with one pair of each.

I think you're right about backwards compatibility of EJ/EH drums onto FB/EK brakes, but I'm trying to scrounge up an EJ/EH drum to compare its internal dimensions with an FB/EK drum.

The Repco drums were finned "the other way" compared with Holden drums.

Rob

[ardiesse]

Fraze (again),

Errol62 has just measured the inside depth of an FB/EK drum and an EJ/EH drum, and it's the same: 2-9/16".
Which means that EJ/EH drums are a straight swap onto FB/EK brakes.

Rob

[DJ]

Rob,

On the other hand, FB/EK drums come in both ribbed and plain varieties.  Usually the ribbed drums ended up on the front and the plain drums on the rear if you had a vehicle with one pair of each.

Which is what I had on my FC when I bought it a very long time ago. To my untrained eye, there was no other obvious difference in dimension or shape.

The Repco drums were finned "the other way" compared with Holden drums.

Just had a look at one trying to image what you mean here. The very edge of the open side forms the first fin on mine. I assume they are Holden.
For Repco, do you mean the first valley was machined on the edge of the open side?

[mcl1959]

All FE FC drums are ribbed, but the costruction is a turned rim welded onto a pressed steel flange.
The REPCO heavy duty drums are machined from a solid single piece I think. The flange is thicker and they are much heavier than a normal drum.

Ken

[fcwrangler]

The difference between the FB/EK drum and the EJ on drum only minor, but could cause problems with the rims. The FB has the same dimples as the FC face where the EJ drums have a flat face. I will do a test fit tomorrow on the FB Vans front end with the EJ drums I have for the FC. I'm also with Ken, I have only seen ribbed drums on the FE/FC, I have seen drums that have ribs across the drum not around. I also have an old PBR drum which ribs around the drum but has a flat mounting face not raised or dimpled
Jim

[DJ]

I have seen drums that have ribs across the drum not around.

I haven't seen or heard of these ones.
With a huge temperature range & the valley running that way, were they prone to cracking?

[fcwrangler]

There was a set or a pair? on eBay late last year for around $300 from memory.
Jim

[customFC]

Regards
Alex

[DJ]

Thanks Alex. I get it now. Cleaver design but what a monster! 

[Errol62]

This is a drum I got with a complete rear axle I took off an EH wagon at Kadina in 1988. The face is not flat.
It doesn't have the raised bits between the stud holes like the FE EK ones do though. I guess that's what was meant by flat hey.

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[Fraze]

Thanks for all of the replies. Looks like all FE FC brake drums were ribbed and most FBs. Eks seem to have had plain drums. It also seems that EH drums will fit FB-EK ------BUT it also seems that you can't use standard FE - EK wheels with the EH drums!!!! A friend is hunting out an old EH drum for me so that I can physically check for myself but it doesn't look good. Cheers, Fraze

[RET]

BUT it also seems that you can't use standard FE - EK wheels with the EH drums!

I've been exploring this further, and I don't believe that's totally true.

The Master Parts Catalogue shows a single part number 7408888 for all wheels from FE up to and including EH. (They also show the same part number for the hub and the bolts all the way through, which is why I think the assertion about mismatched drums and wheels causing drum warp is all bullshit.)

However, as was the case with the introduction of the FE where the sedan came first and the other models followed, so it was with the HD, and there was a run-on of EH utes and vans for about 4 months. It looks like these had HD brakes, so it would be true to say that you can't use FE-EK wheels on EH drums if the drums are from a late (Feb-July 1965) ute or van, for the same reason you have to use HD/HR wheels with HD/HR brakes.

Happy to be corrected by later-model gurus, of course.

[Errol62]

I reckon you could be on to something there RET and it is the HD HR style wheels which cause binding on the early drums.


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[Dr_Terry]

I reckon you could be on to something there RET and it is the HD HR style wheels which cause binding on the early drums.

It's actually it's the other way around. As RET has said all FE to EH wheels (except for those off '65 EH utes & vans with HD brakes) are interchangeable. There are minor changes though, like the size of the valve hole in early rims & whether they are arc-welded, spot-welded or riveted. These wheels will fit FE to EH. If you fit them over the wider HR drums, the drum will be badly distorted. 

HD/HR wheels however, will fit all back to FE.

Dr Terry

[Errol62]

What you say makes sense to me Dr Terry however a very knowledgable member of the FB EK forum insists that he has had an issue with EH rims causing binding on FB EK drums.


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[RET]

Well I reckon his EH drums were the wider HD type. They should be the same dimensions as FB-EK drums, so if they're not, that seems the most likely reason.

[Dr_Terry]

The only instance that I have seen any issue with steel rims fitting over FB/EK drums is with non-original rims which do not have divots to clear the small 'bumps' between the stud holes. The face of the FB/EK drums is not flat like those EJ onwards.

A good example would be the later aftermarket steel rims which are made for caravans & trailers etc. These will fit EJ-HR & Torana, but will damage early drums where these 'bumps' exists.

Dr Terry