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SERIES HILLMAN & SUNBEAM MK III
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ian



Joined: 20 Mar 2012
Posts: 11

PostPosted: Wed Mar 21, 2012 3:23 am    Post subject: SERIES HILLMAN & SUNBEAM MK III Reply with quote

Gooday,

Like JD, just signed up: age 66, have been a Rootes group enthusiast since 1966. Good to have a common link enabling correspondence with like minded. I am in the procees of doing a front brake total refurb on my daily drive Hillman Gazelle.

I split the calipers, then read in the workshop manual that it is not recommended to do so.

Drivers side complete; about to tackle the passenger side now which has a slightly warped disc: probably caused by excess heat at some stage.

Will report on progress and final result when complete.

Ian Moist
Melbourne
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Rick
Site Admin


Joined: 27 Apr 2005
Posts: 20180
Location: Cheshire

PostPosted: Wed Mar 21, 2012 8:16 am    Post subject: Reply with quote

Welcome to the forum Ian Smile

RJ
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Rick (OCC Admin)
Various 1920s-1960s - Austin, Morris, Commer, Dodge etc.
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bob2



Joined: 06 Dec 2007
Posts: 1722
Location: Malta

PostPosted: Thu Mar 22, 2012 8:23 am    Post subject: Reply with quote

Re splitting the calipers, its not that much of a problem, there should be a small rubber washer between them which should be changed if perished when the caliper is split and it should be fine!
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ian



Joined: 20 Mar 2012
Posts: 11

PostPosted: Thu Mar 22, 2012 9:21 am    Post subject: Brake Calipers Reply with quote

Thanks for re-assurance Bob,

The workshop manual is quite clear about not splitting the calipers. It makes me think that there was probably some manufacturers protocol for assembly, and particular factory equipment used for testing, that they wanted to keep in house, connected with the safety liability angle for the risk of front brake failure.

I was able to source some new square section circular seals, manufactured by a company called PBR [ Patons Brake Replacement Pty Ltd; a business which began trading in 1927 in Melbourne, and now an international concern]. They were not cheap at almost $10 Au each.

They appear to be made of a neoprene type material and when seated, sit about .020" proud. Hopefully, they will withstand hydraulic pressure when squeezed up under the recommended bridge bolt torque of 35-40lbs/ft .

Still need wife's car to get other parts to complete. [she works]

Ian
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Kelsham



Joined: 18 Jan 2009
Posts: 349
Location: Llandrindod Wells Powys

PostPosted: Thu Mar 22, 2012 9:34 am    Post subject: caliper rebuild Reply with quote

I always understood that the bolts should be replaced when rebuilding.

The information I had suggested that they were pre tensioned on original assembly.

Having said this. I have heard of people rebuilding calipers without problems.

I have always been cautious and struggled to clean the parts without dismantling.

Perhaps some one has specialist knowledge.

Regards Kels.
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ian



Joined: 20 Mar 2012
Posts: 11

PostPosted: Thu Mar 22, 2012 10:55 pm    Post subject: Reply with quote

You're right Kels, they do stipulate new bolts for re-assembly; not only that, the manual dictates that only new bridge bolts from Lockheed are to be used, and not ones from any other manufacturer.

The bolts themselves are,of course, high tensile, and have the three line marks around the circumference of the bolt head face.

The major brake parts supplier who sourced the crosshead seals said that new bridge bolts were unavailable from the manufacturer, adding that in their experience, it was fairly common practice to refit the old ones.

Common practice is not the 'correct' manufacturers practice though. I can get new high tensile bridge bolts, but they are not from lockheed.

As you mention it could be something to do with thread stretch, but the assembly is static, and once the bolts are in service, I cannot see how they would change, though the manual does state that the torque loadings are critical.

All that can be done is to clean and closely examine the existing bolts for any visible defects before refitting them, which is what I have done.

It is not uncommon though, in workshop manuals, to find that you are instructed to fit new parts on certain assemblies during servicing. It adds up to a blanket cover policy from the car maker,eliminating, in theory, even the smallest risk of possible future failure, at the same time giving peace of mind to the owner / maintainer. It also creates more business from parts sales.

Agree with you, someone with specialist experience from lockheeds is needed to explain the reasons why.

Ian.
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bob2



Joined: 06 Dec 2007
Posts: 1722
Location: Malta

PostPosted: Fri Mar 23, 2012 10:07 am    Post subject: Reply with quote

In both occassions I have re used the same bolts and had no trouble, just torqued them down correctly as per manual, It worked since the leak stopped so as Ian mentioned I think its much more for that little extra revenue for the company than any safety margins!!
But who am I to argue!!!
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ian



Joined: 20 Mar 2012
Posts: 11

PostPosted: Fri May 04, 2012 1:30 am    Post subject: Reply with quote

Well, for anyone following the front brake re-build on my Aus assembled Hillman Gazelle, pleased to report that car is driving daily again now.

The front brakes were de-assembled, and the calipers split.

Supplied and fitted new, were following components:-

1. 2 x new disc rotors
2. New piston seals both sides
3. 4 x New disc pads.
4. 2 x New cross bridge seals [ internal between two caliper halves.
5. 4 x Original bridge bolts were used to re-assemble calipers.

First trip after re-assembly was to Tasmania, via the ferry, but once on the road from home, a slight shuddering was apparent when the brakes were applied, that was transmitted up through the brake pedal, and the steering wheel, becoming a stronger fluttering vibration when braking from speed.

Upon arrival in Tasmania, Pedder Suspension examined the problem, and diagnosed DVT [ Disc Variation Thickness] which simply means that the two faces of the disc rotor are not exactly parallel; and it is measured in thousanths of on inch. A very small difference- perhaps .010", but enough to cause shuddering when you brake.

I had checked run out with a clock gauge on the outer faces, which were within the .004" allowed in the workshop manual, but not both sides of the rotors.

Anyway, a light rotor skim cured the problem, and the car again drives well with more than adequate brakes .[ no servo is fitted on this model]

There are no leaks from the calipers.

Ian.
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Julian



Joined: 19 Apr 2010
Posts: 278
Location: Warrington

PostPosted: Fri May 04, 2012 6:42 am    Post subject: Reply with quote

ian wrote:
You're right Kels, they do stipulate new bolts for re-assembly; not only that, the manual dictates that only new bridge bolts from Lockheed are to be used, and not ones from any other manufacturer.

The bolts themselves are,of course, high tensile, and have the three line marks around the circumference of the bolt head face.

Ian.


I suppose it's worth noting that Lockheed do not manufacture bolts per se, they procure them from a supplier.

High tensile (imperial) bolts with the three line marks are just regular HT bolts, ie grade S or grade 5. You will really struggle to find anything of a lesser quality like Grade 2. Grade S or 5 are just the run of the mill ones on the shelf down the hardware store! I think Lockheed are just spouting baloney to frighten people!

As an aside I've just replaced the '5th' wheel bolts or my artic unit - the stipulation from VOSA was for Grade 8 (6 line marks on the head) to be used. I had to buy them from an American supplier via ebay as I just couldn't get them in the UK! (it was going to be far too much trouble to get VOSA to allow the use of Metric 10.9 grade which would be easy to source Sad )
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