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Z320

hydraulic clutch release bearing (for TR4A-TR6)

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Hi there,

yesterday I had a nice afternoon with my friends A and B (they do not want the be called by name) about our new project,

a full hydraulic clutch release bearing for small money for the "Sachs" clutch.

I don't actually need this, I'm pleased with my old Borg+Beck, 1" slave cylinder and master cylinder reduced from 0.750" to 0.625".

But the day will come to fit a new clutch on my TR4A ....

Friend A is strongly interested in this, also he does not "need" it but likes to bold on his TR more than driving it. So he NEEDS this hydraulic clutch.

Friend B has engine and gearbox out, changes to the "Sachs" clutch and has questions how to make a suitable bearing sleeve and how to modify the gear box front cover.

So the idea was born to fit him the suitable Sachs hydraulic release! Friend A odered it, it was shipped to me and I took a first look on it during the week.

 

Here it is, the gaiter (right on the photo) already off to have a closer look.

1980654670_01Sachshydraulikclutchreleasebearing.JPG.135e924ee59d8a67a9d8c071ce0a5743.JPG

First idea was to check the size of the hydraulic pistion, which is a "ring" on a "guidiance tube" (in the center).

Here you do NOT see the piston, it's in the (grey) body, you see the polished "guidance tube", guess a innervseal of the piston runs on it.  

903327933_02pistonin-guidetubevisible.JPG.f4f84ed6d70be1ee1ad74f9c7e182e52.JPG

Next the (also grey) piston is out, I used compressed air to do this. This is max, you can already see the black outr seal!!!

1905562222_03_pistonoutwithpreassuredair.JPG.56144f1399a724e6f898a1ae4e093d6c.JPG

Compared with the original slave 1" and with consideration of the leavers on the clutch shaft, 87 mm and 65 mm long,

the size of the surface of the ring pistion is about 10% more. This will reduce the force about 10% by the need of 10% more way.

That's OK for friend A, B and me.

429569981_04leaversontheclutchshaft.JPG.ee3cad37ab7875f5a9318e886a43a856.JPG

Beginning with the modifications the unit had to come off the aluminium plate on which it was screwed on, it is too high, I dad to drill the screws.

1821225603_05drilledthescrews.JPG.6a290caadbacd7a36a1cbc2af03ae4a1.JPG

Next will be to remove this clip and make a new one with inside a minimum of more diameter.

873776847_06Clipmustbemodifiedtogettheshafttrough.jpg.39dff5729d6c64e8d0b2dadb68a86ba1.jpg

To get the original gearbox shaft through.

22375751_07gearboxingoingshaft.JPG.cbe524362b60baf7ab71e32c5af04e6f.JPG

Yesterday was the meeting of us with this nice engine, the gearbox, the old Borg+Beck and the new Sachs.

850020857_08The6cylinderengine.thumb.JPG.04ce2dd7b38c1181d875e4242fab6692.JPG

With the long leaver and the luggage scale we pulled the Borg+Beck and the Sachs to see the difference - to our surpice with no basic difference

- old Borg+Beck with the (big diameter) original release bearing: 106 kg

- new Sachs clutch with the big original release bearing: 112 kg

- new Sachs clutch with new small Sach release bearing: 112 kg  !!!

Is all about what is told about "logical" - but indeed wishfull thinking?

 

On the gear box we checked the deept of the bell housing (sorry, no photo) and fixed a mounting rail on the engine in this distance.

Fortunately the Borg+Beck was like new so we have been able to determine the "air" the old engineers gave on the original sleeve for the abrasion of the clutch.

With the abrasion the spring will come out of the clutch body and moves the release bearing closer to the gearbox!

897409274_09gaponthebearing.thumb.jpg.214a54f89584efeabaf3b8f289bba8bc.jpg 

With the Borg+Beck unfastened ("same" like full worn) there still remains a small gap.

Knowing this we worked with the Sachs the same way and found this the suitable lenght to modify the cover plate.  

1693904415_10checkhighofthecover.thumb.jpg.daabbcb9e54243c71d0f4b58f7bb7266.jpg  

Material is ordered, could be ready next weekend.

What do you think about.

Ciao / Cheers Marco

Edited by Z320

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Hi Marco,

nice project.

Since the new design gets rid of the friction losses in the clutch shaft bearings and pivot points it should operate at a reduced pedal force.

There was an article in the Dutch TR magazine last year, I think they used an US made hydraulic cilinder, similar to what is used by a UK TR specialist in their kit.

I wonder if overstressing the diaphagm as a result of a too long stroke is an issue? Probably not since the new cylinder requires more oil (volume) for the same stroke, if I have understood your post correctly.

The vent connection should be at the 12o’clock position, but you thought about that I guess?

Good luck and keep us informed please.

Cheers,

Waldi

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Marco,

nice...keep us posted. I hope it goes as well as your Power Steering Project. 

Jochem

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We did not use the Opel Omega unit.

This is our HOWE:

 

754607353_Howe8285.thumb.jpg.10da69bcf6476d46ed9332795898612d.jpg

 

Although specified being not suitable for a normal clutch, it will do the job.

It is advertised for a 0.75" master cylinder.

 

Edited by TriumphV8

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Hi Andreas,

is there a reason for not using the Sachs unit for Opel Omega?

To adapt it is quick and easy.....

2137532937_11coverwithreducedhigh.JPG.c41cba051061c5568194c6ee5ee38038.JPG

Made the cover shorter and cut away the tube.

1943141028_12coverwithadaptorplate.JPG.ead625e3fb0baf14a0704866d08af37b.JPG

Suitable adaptor plate.

658975654_13firstfit.thumb.JPG.3b2365310c9efe9f887d878964525b4c.JPG

Like playing with Lego, will be finished soon, until this we are play dice who will be the bravest of us to test it.  :ph34r:

Ciao/Cheers, Marco

 

Edited by Z320

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From the "Howe Racing Enterprices" website: "Fully compressed the unit is 2-3/8” thick.."

That's about 10 mm more than the Sachs unit and you have to do a special modification on the gear box cover because of the oil seal.

With the Sachs unit we can stay away from the seal, but this was our risk with the order and by accident.

 

Edited by Z320

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By the way I always worried about the condition of my clutch,

7 years ago it was out and I put it back again against other advices, about 7 mm thick.

You know, it is not possible to measure its thickness with the gearbox in!

 

Indeed you can! Professional car mechanics will know this, but until today not me.

 On our meeting at saturday we measured how far the fins of the clutch come out on the old B+B when its worn (= not tight bolded).

Thats about 7.5 mm, 10 mm may be the sencefull air for the sleeve to the gearbox cover for the clutch's abrasion over the years, we measured 11 mm.

Remains about 3.5 mm air when the clutch is worn.

On the outer leaver of the clutch shaft this is 11 mm / 87 mm x 65 mm = 14.7 mm play down to 3.5 / 87 x 65 mm = 4,7 mm play over the years!

On my TR4A it is 10.5 mm, everythink is OK, this clutch will further serve me long years. Not 100% correct, but an indication.

Ciao/Cheers, Marco

 

 

 

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Hi Marco, the reason to choose the Howe was simply that somebody did that before and Waldi sent me a picture.

We had to cut off the nose up to close before the oil seal.

It fits like it was made for that purpose. Funny that the pattern of the 4 bolts is perfect.

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Sometimes its just luck.

It sits slack between the 4 bolts? Can not see any nut.

Edited by Z320

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On 3/5/2019 at 9:49 PM, Z320 said:

It sits slack between the 4 bolts? Can not see any nut.

Yes, original it was designed that in a similar construction two screws

are released and only two longer threaded bars are inserted and the

unit with the oil seal is fixed with a nut. Than two nuts each side are

mounted and in the proper distance fixed against each other.

I prepared the pins to accept a little rubber ring to get a nice clamp.

Howe02.thumb.jpg.f6a993fd10e51c8dda5492c7f9aa8d65.jpg

 

Proper distance is set with the two shims at the bottom of the pins.

It is quite critical to have enough space for the clutch to wear but

not too much travel without any movement of the clutch.

 

We fitted childs rubber (Knete) to get an imprint on the release bearing.

Edited by TriumphV8

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"Knete" is indeed sometimes a usefull helper.

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11 minutes ago, Z320 said:

"Knete" is indeed sometimes a usefull helper.

Ahh !!

play-Doh 

:D

C30EF56C-4712-4EEF-9A0C-9D9A273ED526.jpeg

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Yes, exactely what we had. Looks like teeth when

you have the imprint of the spring on it.

Than you peel it from the bearing ans measure the thickness

to get an impression of the play between bearing and spring.

2mm was recommended by Cambridge Motorsport.

 

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2 mm is not very much, this is only about 0.7 mm abrasion on the clutch plate, we give it more....

The reason I asked for your slack hydraulic unit is, not bolded on the gearbox or a back plate most of them are not sealed.

They look like this from underneath, the preasure of the brake fluid will press the guidance tube out istantly.

 IMG_4214.thumb.JPG.552ce7c0283b569b0cd433976f71e987.JPG

Only strongly bolded on the back plate this keeps sealed, the 1 mm offset is to compress the seal inside the unit.

Yesterday I pulled the upper clip away and hoped to get the gear box shaft through - no way, only about 1/10 mm too small.

With the clip off the unit goes in its pieces very easy!

P1120085.JPG.850b63c30a7ca617afbd8e89eefec309.JPG

1 = body, 2 = piston with seal, looking on the seal side, 3 = guidance tube, 4 = clip holding all together, 5 = release bearing, 6 = gaiter, 7 = spring (bearing is alway running, pressed on the clutch, 8 = upper ring to fix the gaiter, 9 = the lower one for this.

Fitted all together again, on the DIY adaptor plate, in the lathe to grind (Dremel) the inside diameter larger up to 32 mm.

P1120084.JPG.647bf4c2b384a1b096fafd7ceb79b4f1.JPG

Shaft goes throught now, but a clip inside the tube to keep it together again does not work.

So I made a ring of bronze, 2 mm high and pressed it on the guidance tube.

P1120091.JPG.a00ddd7b50776c84bc8089a9f58e62ab.JPG

Ready, waiting for material and tomorrow is TR-Stammtisch.....

P1120087.JPG.51753e806f14eef284f2fc881404dde6.JPG

Ciao Marco

 

Edited by Z320
My bad english writing

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Nice work from our continental friends, the slightly different approach and engineering around the various challenges will bring about very interesting developments and the result will allow many of us to adopt or buy from them if it is marketed. We are all getting to the age where a reduced clutch pedal pressure and betterment of reliability of the clutch operation will be appreciated by many.

Mick Richards

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9 hours ago, Z320 said:

2 mm is not very much, this is only about 0.7 mm abrasion on the clutch plate, we give it more....

The reason I asked for your slack hydraulic unit is, not bolded on the gearbox or a back plate most of them are not sealed.

I was not very pleased with these details, too.

But as Cambridge sells their system with those details and

many cars are driving with that HOWE unit, I will rely on that.

 

The other idea was to find a salon gearbox, that has the smaller shaft

where many units slide easily over the input shaft.

 

 

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11 minutes ago, TriumphV8 said:

I was not very pleased with these details, too.

But as Cambridge sells their system with those details and

many cars are driving with that HOWE unit, I will rely on that.

Hi Andreas,

always check twice what you have been told,

and perhaps sometimes do things different than the mainstream.

Ciao, Marco

Edited by Z320

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Hi,

was on the "Retro Classics" Stuttgart this weekend looking for gearboxes with ingoing shafts with diameter 31 - 32 mm.

Found some, BUT on all of them the shaft is taller, even on Mercedes, BMW and Porsche, only 24 - 28 mm.

Had a nice talk to a guy from ZF (gearbox maker), they make shafts 32 mm only for Ferrari und Maserati.

So I have no hope to find a standard hydraulic for a nice price that fits our TRs without modification...

(by the way, the Opel / Vauxhall Omega unit is on sale occasionally for 45 - 50 Euro)

Will continue work on the unit tomorrow.

Ciao Marco

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Sorry to read that.

You may finish the job as a set for the saloon gearbox

as a DIY kit just to fit out of the box..

Many have that in use on the TR6 and will be happy to

have that improvement.

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Hi Andreas,

we have two shafts as master pieces,

one 30.60 mm, the other 31.60 mm, both do not go through.

You agree with me, it is easier to modify the OVO (Opel-/Vauxhall-Omega) hydraulic unit than to buy another gearbox ;)

Ciao, Marco 

Edited by Z320

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new, bigger adaptor plate is ready

2127221103_14newadaptorplateready.JPG.032efb665f7d16c4e27439867937d6fa.JPG

to fix it on the 4 threads of the gearbox cover I had to bring all 4 to the same high

1809161194_15bringthedrillsofthegearboxcovertothesamehigh.JPG.859a6250899848257acc11430a046b66.JPG

lowest was 9.35 mm high, is now 9.30 mm

1440016202_16bring9.35mmto9_3mm.JPG.5434a7291244902c31368a99ae9c8b1d.JPG

 

highest was 10.5 mm, is now also 9.3 mm

1543760641_17bring10.5mmto9_3mm.JPG.dc73f3deb788996141b2ce228bf86330.JPG

working on the connectors my 5/16 UNC tap went worn, have to order a new one...

1891513743_18connectors.JPG.264a50660f8624f21a3bd2ddfaa4efd9.JPG

 

Edited by Z320

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Nice to see that the story goes on.

 

I understood you finished and want to sell the rest.

 

We got the AN-4 units and will finish the piping next days.

Cambridge Motorsports has a nice sheet aluminium that bolts left side

of gearbox and with two bulkhead connectors a very good

solution to separate the piping can be established.

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Hi Andreas,

this is about how we do it and how everyone can make this his own project,

this with the hope to get some advice / help from others and benefit from their experience.

We do not want to sell anything. When the first unit works, we will only do 2 more (A, B and me).

Ciao / Cheers, Marco

 

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Hi,

a question from Russel at another thread made me realize we lost the drill on the ground of the guidance tube (left).

I suppose this is to drain oil from a leek lip seal to avoid to get it throuhj the tube in the clutch / on the friction plate (and to oil the sleeve on the tube).

1627111230_19oildrills.jpg.98ce0c8d989e8fa9ee9cc4ba7efc2f68.jpg

This is how I solved it.

1694157007_20newdrill.JPG.9157227dbedbbb67a78b23d40a883c3e.JPG

A ring made of 3 mm spring steel keeps the lip seal on distance to get a gap to drain the oil.

This will fit anyway, the seal is taller than the seal seat.

1458985095_21lipsealdistancer.JPG.89ee0b584efdb4294361053c191ff0f7.JPG

New tap 5/16 UNC is in, connectors are ready, only waiting for this "§$%&/! bolts....

Ciao / Cheers, Marco

Edited by Z320

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