Brake Servo Failed

[ProjectChimaera]

Think this one might have had it! Mighty glad it deposited huge quantities of brake fluid in the footwell before I got new carpets etc.
Removing the master cyl, servo and pedal box isn't much fun. For future info, releasing the pipes from the connection block on the bulk head, undoing the master cylinder bolts and releasing the pedal box allows the master cylinder and pipes out through the top with the reservoir removed.Detatched throttle pedal and pivot spindle from pedal box, also bonnet cable. Split servo from pedal box and the pedal box will come out without removing steering column. It's much easier to undo the pipe connections to master cylinder in the vice as mine were brass and very tight.
I knew there was a lot of fluid in the servo by dipsticking the servo through the vacuum hole. Scarily I poked around the servo rusty bits a little and the two halves separated.

[ClassicChimaera]

What year is your car.

[portzi]

ClassicChimaera said:

What year is your car.

Well it's between 1992 & 2003, so it's all very scary the point is you don't know which one is rotten until you have changed yours out!!!!!!.

I would hope all Chimaera's and Griffith's, no matter what mileage will have either had the servo replaced or getting it inspectioned for potential failure.

I would certainly not buy an pre 2000 TVR without the servo being replaced or checked .

[ProjectChimaera]

ClassicChimaera said:

What year is your car.

1998 vintage!
It's pretty amazing that with all new brake pipes and calipers etc. that it all bled up well with a good pedal and servo operation!
Only after it was left standing did it leak back and out!

[coupe20vtnz]

I have a 1996 - And it looked exactly the same when I pulled it out.

Mine 1/2 worked - only after 10-15mins driving did it start to develop a fault - the pedal wouldn't release...

You are right - not the easiest job - just take you time....

[KateV8]

This was ours at Powers and our car is one year younger than the one elsewhere in this thread. Dom couldn't get a brake pedal after changing the rear calipers and found both the servo and master cylinder had failed. By coincidence it was in my list of things to be checked this Winter but the failure preempted the inspection by a month or so. I now believe the servo is as much a safety issue as fuel pipes, if you've never seen yours get it checked and replaced as necessary.

[bobfather]

I went through the clutch reservoir cover with a snake cam to check mine last summer, there's a little surface rust but nothing too serious. I just made sure it was dry and applied some wax treatment to preserve it a little longer. BTW 1999 Chim with 62k miles

[N7GTX]

So thought I'd look up some prices for a brake servo. TRW PSA 328 and Bosch 0 986 485 090 for a Ford Fiesta Mk3.

TVR Parts - £195+vat - http://tvr-parts.com/tvr-parts/part-details/tvr-j0...

Powers Performance - £449.99+vat - http://www.powersperformance.co.uk/store/slug/brak...

Racetech Direct - £455+vat - http://www.racetechdirect.co.uk/car-parts/brakes/c...

eBay (as of now) - £291.50 - http://www.ebay.co.uk/itm/TVR-Chimaera-Griffith-TR...

Best Parts Store (based in Germany)- £307.98 inc vat + postage - http://www.bestpartstore.co.uk/2210981

However, Best Parts Store (Germany) sell the equivalent Bosch unit 0 986 485 090 for £109.98 inc vat + shipping - but don't know if genuine or copy - http://www.sparepartstore24.co.uk/7126699-bosch

This article explains in detail which servo and which master cylinder will fit plus any slight modifications you may need to make.

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Hopefully someone will be along with a nice cheap supplier...... Maybe Simon (Sardonicus)

[s p a c e m a n]

Fookinell, cheaper to fit a pedal box than buy from the usual places isn't it

[RobXjcoupe]

The brake master cylinder failed on my Griff about 3 years ago, servo wasn't too bad, with a bit of surface rust. The master cylinder was of fiesta 1.8 diesel spec though. Was wondering if the slightly later fiesta mk4/5 have the same servo as the mk3 fiesta. Same basic car?

[RobXjcoupe]

The above pictures are of my w reg fiesta mk5 servo. I'm happy to measure up if that helps?

[FoxTVR430]

OMG that's worrying! mines a '93. I've had the slave cylinder exchange by Mat Smith but not sure about the servo.
Time to check me thinks.
So remove the brake reservoir cover and use a snake cam to check the servos condition. is that the way to go?

[bobfather]

FoxTVR430 said:

OMG that's worrying! mines a '93. I've had the slave cylinder exchange by Mat Smith but not sure about the servo.
Time to check me thinks.
So remove the brake clutch reservoir cover and use a snake cam to check the servos condition. is that the way to go?

Clutch cover

Also, it may be difficult to detect internal rust from leaking master cylinder. Look for a wet surface, that would indicate that something may be going on inside

Edited by bobfather on Friday 13th January 08:47

[N7GTX]

RobXjcoupe said:

The brake master cylinder failed on my Griff about 3 years ago, servo wasn't too bad, with a bit of surface rust. The master cylinder was of fiesta 1.8 diesel spec though. Was wondering if the slightly later fiesta mk4/5 have the same servo as the mk3 fiesta. Same basic car?

Looked this up. The Mk3 Fiesta had an 8" servo and the Mk4 has a 9" servo. So unless someone has actually fitted one it doesn't look good.

[RobXjcoupe]

N7GTX said:

RobXjcoupe said:

The brake master cylinder failed on my Griff about 3 years ago, servo wasn't too bad, with a bit of surface rust. The master cylinder was of fiesta 1.8 diesel spec though. Was wondering if the slightly later fiesta mk4/5 have the same servo as the mk3 fiesta. Same basic car?

Looked this up. The Mk3 Fiesta had an 8" servo and the Mk4 has a 9" servo. So unless someone has actually fitted one it doesn't look good.

I imagine in true Ford fashion the mk4 fiesta version bolts up the same as the earlier version. It's the clearance needed within the TVR.? I have no idea if it's a close fit or has room around it to accommodate the slightly bigger servo? £30 buys a second hand fiesta mk4 brake servo, just need someone with their TVR apart to try it?

[portzi]

RobXjcoupe said:

N7GTX said:

RobXjcoupe said:

The brake master cylinder failed on my Griff about 3 years ago, servo wasn't too bad, with a bit of surface rust. The master cylinder was of fiesta 1.8 diesel spec though. Was wondering if the slightly later fiesta mk4/5 have the same servo as the mk3 fiesta. Same basic car?

Looked this up. The Mk3 Fiesta had an 8" servo and the Mk4 has a 9" servo. So unless someone has actually fitted one it doesn't look good.

I imagine in true Ford fashion the mk4 fiesta version bolts up the same as the earlier version. It's the clearance needed within the TVR.? I have no idea if it's a close fit or has room around it to accommodate the slightly bigger servo? £30 buys a second hand fiesta mk4 brake servo, just need someone with their TVR apart to try it?

there is quite afew rebuild threads on here, so perfect time for them to change their servo's out whilst cars in bits.

I had my brake servo changed 5 years ago during my full rebuild, I would advise those doing this right now to do the same, plus looking at there clutch master cylinder and slave for leaking and corrosion.

[KateV8]

Sardonicus said:

They rot out because MC leaks go unchecked and lay in the servo body absorbing moisture even further and doing its best work over years rotting out the base that one above was so trying to tell the owner it was leaking fluid into the servo chamber thats why the paint is stripped from brake fluid dampness creeping from the MC to servo join, a simple clutch fluid level check and a peer through the hatch would of exposed that mess earlier I do wonder about how much inspection these cars actually receive at service time or keen DIY owners

Point taken.

[Sardonicus]

KateV8 said:

Point taken.

It wasn't a personal pop I was aiming at a bigger audience

[KateV8]

Sardonicus said:

t wasn't a personal pop I was aiming at a bigger audience

I know, sorry I actually meant thanks for teaching me something I didn't know . Glad people like yourself are on here to help the rest of us out especially with safety critical stuff

[N7GTX]

RobXjcoupe said:

N7GTX said:

RobXjcoupe said:

The brake master cylinder failed on my Griff about 3 years ago, servo wasn't too bad, with a bit of surface rust. The master cylinder was of fiesta 1.8 diesel spec though. Was wondering if the slightly later fiesta mk4/5 have the same servo as the mk3 fiesta. Same basic car?

Looked this up. The Mk3 Fiesta had an 8" servo and the Mk4 has a 9" servo. So unless someone has actually fitted one it doesn't look good.

I imagine in true Ford fashion the mk4 fiesta version bolts up the same as the earlier version. It's the clearance needed within the TVR.? I have no idea if it's a close fit or has room around it to accommodate the slightly bigger servo? £30 buys a second hand fiesta mk4 brake servo, just need someone with their TVR apart to try it?

When you look down into the void under the clutch master cover, the clearance on the outside is very tight at the bottom.
You can get an idea of the condition of the brake servo by opening the driver's door, getting down on your knees and with a torch look towards and behind the accelerator pedal. About a third of the servo is clearly visible behind the accelerator pedal on the outside and if yours was as bad as those in this thread you would probably see it here. You can also check for any leaks from both the brake and clutch master cylinders while you're at it.
Then get someone to help you get up off your knees.....