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Tr4 brake servo


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  • 4 years later...

Hi Guys,

Owning  a TR6 and now also TR4A, I have been reading up the pro's and con's of fitting a servo to the TR4A.

Clearly there are different views on whether a servo is needed on a TR4 and TR4A, but I do like driving the TR6 with one fitted by design.

However, I can't seem to reconcile the views of some that fitting a servo to a TR4A is not necessary, but  the factory fitted a servo to a TR5, which has the same body/braking/running gear as the TR4A?  Yes the engine is slightly heavier in the TR5, the same as the TR6, but all three have the same chassis and independent suspension.

So if it works for a TR5, why not retrofit a remote servo to a TR4A and 'improve' the braking performance to the same standard as the TR5?

Rich

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39 minutes ago, rvwp said:

why not retrofit a remote servo to a TR4A and 'improve' the braking performance to the same standard as the TR5?

It doesn't make any difference to braking performance Rich - it just reduces the pedal effort required to achieve it.   Just down to personal preference really. 

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I vaguely remember a posting some years ago on this subject stating the seals on aftermarket servos don`t like silicon brake fluid causing sticking problems but not sure which ones.

Cheers Chris

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As TRs went further up-market, the car was attracting a different type of customer - people who expected cars to require somewhat less effort in driving.

Rack & pinion steering reduces effort and is more precise, adding power assistance to braking reduces pedal effort, wind-up windows means no more fiddling to fit sidescreens.

That said, the disc brakes on a TR are excellent and, even for an old and small man (i.e. me) do not require power assistance.  Just my opinion, of course.

Ian Cornish

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1 hour ago, rvwp said:

Hi Guys,

Owning  a TR6 and now also TR4A, I have been reading up the pro's and con's of fitting a servo to the TR4A.

Clearly there are different views on whether a servo is needed on a TR4 and TR4A, but I do like driving the TR6 with one fitted by design.

However, I can't seem to reconcile the views of some that fitting a servo to a TR4A is not necessary, but  the factory fitted a servo to a TR5, which has the same body/braking/running gear as the TR4A?  Yes the engine is slightly heavier in the TR5, the same as the TR6, but all three have the same chassis and independent suspension.

So if it works for a TR5, why not retrofit a remote servo to a TR4A and 'improve' the braking performance to the same standard as the TR5?

Rich

My wife would not drive our 4A because she found braking hard work. I fit a servo last year and she can now cope with the car.

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The proof of the pudding as they say.....I put one on when I came out of the boot, having ruptured my Achilles’ tendon and decided that it was worthwhile while recovering and never took it off. 

Buy one of the cheap kits and try it. If it works well and you are happy then fine, but if you don’t like it take it off.

I appreciate that some will say that you must fit an original but they are way more expensive and most of the cheapo ones work fine.  I bought one as an original from one of one of the major dealers only to find it wasn’t and was told it was “originall style” as the Lockheed ones were out of supply ,to which my response was if I was going to get repro, I might as well pay repro prices and sent it back and bought the same kit for vastly less on eBay.

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If my 4A didn't have a servo fitted when I bought it, having driven others without the servo I most certainly would have fitted one to mine, to me it makes the driving experience so much more pleasurable as I'm not into the hairy chested macho philosophy of if you can lock the brakes you don't need one.  If it makes driving more pleasurable for you when you don't need the legs of a second row to brake, then go ahead and fit one. There aren't many TRs out there that can be called 'original' now anyway.

Mine's a Lockheed.

 

 

20200812-P1050018-2.jpg

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Looks like I need to do some more investigation in to the servo as mine was on the car when I got it all works well, does as it should when being tested no problems when I bleed the brakes but what is being said is that the white part should not be on the top!

Mike Redrose Group 

9DE8B1AB-8534-40A8-9CD9-5D4192298B4C.jpeg

Edited by BRENDA1
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Hi Guys,

Um! interesting responses to the 'whether to fit a Servo' or not.

I understand the argument that 4/4A's were not fitted and the reason why the 5/6's were, that drivers wanted more refined driving. Well, as my 1965 Sunbeam Tiger and 1972 TR6 both were factory fitted with a servo, and now being in my mid 70's, refined driving is the order of the day.

Why make driving difficult, So I think I will fit a servo.

Regards

Rich

 

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Folks, I’ve toyed with the idea of fitting a servo to my TR4A. On the Moss US site, they list one type; a black unit with a white valve body. However the Moss UK site lists two types; Lockheed and “Aftermarket”. The Lockheed one has a cadmium like finish, while the “Aftermarket” looks the same as the one offered at Moss US. Anyone know the difference in these two units?

Jim

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  • 2 weeks later...

I have a Mot-a-Vac unit and it's very good.

They crop up from time to time.

No problems with silicone fluid since rebuilding and greasing seals with MolyKote silicone grease.

Compared to previous Lockheed-type servo it is much less intrusive and still has good feedback. I have driven a rally-prep TR4 without a servo and the difference is noticeable.

Cheers

Ade

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Hi, what about this?

I went onother way because the TR4A brake is good enough for me and a brake servo could cause me some trouble with the German TÜV.

The Ford Cortina Girling brake cylinder (it's sold me this way) looks the same like the TR4/4A (big body) - but is 0.625" diameter instead of 0.700".

So the boost is 1.20, on TR4s with Girling 0.750" master the boost is 1.44!

You can't see any difference at all, only the cast ring (one on 0,75", two on 0,70") is missing, nobody ever realised it.

I found it as a bargain on eBay.

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Which other way do you get so simple a 20% stronger brake!?!

Ciao, Marco

 

Edited by Z320
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