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Servo not working? Alternatives?
Posted: Sun Aug 16, 2015 8:16 pm
by tony g
On my sprint Ive noticed the lack of assistance when pressing the pedal with engine off and then firing up. The pedal doesnt move any noticable amount at all so I am thinking its capput! The pedal is firm and the brakes are ok as I have a set of trackerjack brackets and made my own kit from that. I didnt notice that the pedal was a bit wooden maybe because of the better brakes on there.
Sooo question is , is it worth trying to fix this servo or fit another from another car? If the latter what comes close to fitting?
Cheers
Tony
Re: Servo not working? Alternatives?
Posted: Sun Aug 16, 2015 8:44 pm
by GrahamFountain
It depends what's gone.
I've got one the internal diaphragm's gone on - the master cylinder leaked into it and it's split. I know there are a few NOS diaphragms out there - I think it's Fitchetts are still offering a recon service. But it's not a cheap option. Think there may be a grimmer place that has them, though they were awaiting new stock last I looked. Mine's gone off to one of them B places north of Manchester: Bury, Burnley, or Blackburn. But I've not heard back yet.
If it's the outer seals that have gone, there are repair kits from all an' sundry and grimmer.
Pro temps I've got a s/h one from a scrapper - £50 with the master cylinder still attached. But I'm still waiting to find out if that works.
Graham.
Re: Servo not working? Alternatives?
Posted: Sun Aug 16, 2015 9:06 pm
by GrahamFountain
As to alterntaives, there was some discussion on that here:
viewtopic.php?f=4&t=29405
However, looking at one XR3i servo, it's not clear to me it's a replacement.
Re: Servo not working? Alternatives?
Posted: Sun Aug 16, 2015 9:21 pm
by tony g
Thanks Graham I'll have a look for Ford stuff then
Tony
Re: Servo not working? Alternatives?
Posted: Sun Aug 16, 2015 9:49 pm
by tony g
Just searching for servos to get images etc. Im now wondering how the Mazda MX5 would dimension wise. Has anyone here got one to measure the studs pcd?
Tony
Re: Servo not working? Alternatives?
Posted: Mon Aug 17, 2015 1:52 am
by gmsclassics
The easiest alternative is that from an 1850 engined Dolomite. No modifications required, it is just a little smaller in diameter. Although the theory says that the level of assitance must be less, in the many years I ran one in one of my Sprints, I could never discern any noticeable difference when driving. Just depends whether you can find one from an 1850 is reasonable condition.
Geoff
Re: Servo not working? Alternatives?
Posted: Mon Aug 17, 2015 8:47 am
by tony g
Geoff I have no problem using an 1850 one but the scarcity is getting to all models of Dolomite now I suspect. I dont really want to spend good money on something that will fail again so a modern alternative that we can all use would be a better solution I think.
Tony
Re: Servo not working? Alternatives?
Posted: Mon Aug 17, 2015 9:50 am
by geeksteve
tony g wrote:Just searching for servos to get images etc. Im now wondering how the Mazda MX5 would dimension wise. Has anyone here got one to measure the studs pcd?
Tony
I have an MX5 and a Dolly, doing an engine swap between the two in fact.. I can compare them for you, but I am hideously forgetful and unreliable.. I'll try my best
Steve
Re: Servo not working? Alternatives?
Posted: Mon Aug 17, 2015 10:39 am
by AlanH
Possibly one here
viewtopic.php?f=4&t=29353&hilit=what+to+save
I'm intrigued by this. The shortage is obviously there so were these specially made for the dolomite?
Re: Servo not working? Alternatives?
Posted: Mon Aug 17, 2015 10:54 am
by tony g
I was hoping you were going to say that Steve

Be great to get the bolt pattern through the bulkhead first if its easy to get to.
Cheers
Tony
geeksteve wrote:tony g wrote:Just searching for servos to get images etc. Im now wondering how the Mazda MX5 would dimension wise. Has anyone here got one to measure the studs pcd?
Tony
I have an MX5 and a Dolly, doing an engine swap between the two in fact.. I can compare them for you, but I am hideously forgetful and unreliable.. I'll try my best
Steve
Re: Servo not working? Alternatives?
Posted: Mon Aug 17, 2015 11:44 am
by geeksteve
tony g wrote:I was hoping you were going to say that Steve

Be great to get the bolt pattern through the bulkhead first if its easy to get to.
Dash board is sitting in a pile behind the car, so shouldn't be too tricky to get to..
Steve
Re: Servo not working? Alternatives?
Posted: Mon Aug 17, 2015 11:04 pm
by trackerjack
On the special I have no servo and the bigger MX5 brakes from the 1.8 and the Porsche 944 has a servo as does my Quantum which being RS turbo mechanicals has a servo. All these cars stop okay and all can lock their wheels however when I step into wife Dianes driving school Fiesta turbo (she is an AA driving instructor) I only have to look at the brake pedal and it leaps to a halt!
Conclusion is. If your used to modern brakes make allowances for old crap

Re: Servo not working? Alternatives?
Posted: Tue Aug 18, 2015 3:00 am
by cleverusername
tony g wrote:On my sprint Ive noticed the lack of assistance when pressing the pedal with engine off and then firing up. The pedal doesnt move any noticable amount at all so I am thinking its capput! The pedal is firm and the brakes are ok as I have a set of trackerjack brackets and made my own kit from that. I didnt notice that the pedal was a bit wooden maybe because of the better brakes on there.
Sooo question is , is it worth trying to fix this servo or fit another from another car? If the latter what comes close to fitting?
Cheers
Tony
Daft question, but you have checked for a leak in the vacumn pipe?
Re: Servo not working? Alternatives?
Posted: Tue Aug 18, 2015 7:05 am
by tony g
Not a daft question at all. Yes I have checked that. Clamping the servo pipe near the manifold makes no difference to the running,even pumping the brakes while running doesnt change the engine note.
Tony
Daft question, but you have checked for a leak in the vacumn pipe?[/quote]
Re: Servo not working? Alternatives?
Posted: Tue Aug 25, 2015 5:52 pm
by Toledo Man
Another obvious question Tony: What about the one way valve? Is that working? I had to replace mine a few years ago. Fortunately, somebody on this forum was able to supply me with the necessary part.