300mm Front Brake Conversion(with pics!)

[N7GTX]

After reading some old posts on here about the 300mm front brake conversion, decided it might be a good idea as the insurance company's next question after telling them the car had a turbo was, "Have the brakes been modified then?"

The original discs were 240mm...


I bought reconditioned calipers from Euro Car Parts. I chose Pagid ones as I've always found their stuff good quality. Their part numbers are 133590311 and 133590324 for left and right. Simply enter them into the search box on the home page:
http://www.eurocarparts.com/ecp
They cost £62 each plus vat and a surcharge of £25 per caliper so if you do not have old ones to return you will pay this. Then the total price would be £208.

To keep costs down, I sourced carriers from a scrapyard. They were from a Ford Mondeo Mk3 and are all the same size. You cannot use the Mondeo discs as they are 5 stud. If you want to buy the carriers separately they are often on eBay and the Bosch part number is 0204Y01125. They are not handed so just order 2 of them.


The discs are from a Ford Focus ST170 and are 300mm. The Euro Car Parts number is 104590548 and cost £25.21 each inc vat. They are vented, 24mm wide, 4 stud and the center hole is the same size as the hub.


The brake pads are again Pagid, for a Ford Mondeo Mk3, from Euro Car Parts, part number 101590298 costing £26.58 inc vat.

After removing the old calipers and discs there are 2 adjustments that need to be made.
1. The mounting holes on the hub - 10 mm - need to be enlarged to take 12 mm diameter bolts. A 12mm drill bit does this very easily.


2. Due to a difference in offset between the discs it is necessary to buy 4 longer mounting bolts and then fit a spacer on each one. You can see the gap between the carrier and the hub in this picture. The gap was 15mm. I used washers to accurately measure the gap.
I got M12mm x 40mm socket head high tensile screws, grade 12.9, from a local supplier, Kays Fasteners, for £2.50. I used the tubes from old suspension bushes I found in the scrapyard that were 12 mm diameter and then cut them to size as they are thick walled and strong.


For clarification these are the actual screws fitted, not the silver plated ones used to set up and measure in the picture above.

|http://thumbsnap.com/Enh7j5aM[/url]

I painted the carriers and calipers with red Hammerite Smooth paint from B&Q for £8.48 giving them all 2 coats.
http://www.diy.com/departments/hammerite-red-gloss...

This is the result:


Once they were all assembled and fitted, the new brakes were bled with 6 pumps of the pedal on each side enough to expel all the air. The wheels were fitted. Mine are the original 15 inch diameter ones so this is all a close fit. The passenger side wheel went on okay with a gap of just 0.5mm.
However, the driver's side was just catching between the rim and the corner of the caliper. By turning the wheel a few turns a mark was left in the newly painted caliper. I then hand filed this until I had the clearance. The calipers are cast so this is an easy fix.


I painted the caliper again and fitted the wheel. This is the result.



If you want more stopping power you can get drilled and grooved discs from companies such as Demon Tweeks and Tarox. The Tarox website lists 3 types and this gives an idea of what is available for standard Chimaera replacements.
http://www.tarox.co.uk/shop/tvr/chimaera/?filterin...

You will need the Ford Focus ST170 300mm ones shown here:
http://www.tarox.co.uk/shop/ford/focus-mk1-98-05/p...

If you are doing track days then you will probably also need uprated brake pads which are very much a personal choice.
For the observant out there, you may have noticed the Mud and Snow tyres on the front of the car. Someone obviously wanted a very cheap set to sell it. I have 4 new ones on order.

I hope this helps anyone considering this upgrade.

P.S. Although there is clearance between the wheel and caliper it is quite tight if on original 15" wheels. If you have 16" or above then no issues at all.
For my own peace of mind I have now fitted 3mm wheel spacers all round at £5.49 a pair.
http://www.ebay.co.uk/itm/3mm-Alloy-Wheel-Spacer-S...

Edited by N7GTX on Friday 28th August 14:45

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Edited by N7GTX on Friday 28th August 15:34

Edited by N7GTX on Friday 28th August 15:39

Edited by N7GTX on Monday 31st August 11:10

[N7GTX]

TVRMs said:

Looks like you're about ready to loose your balance weights?

No, they just get past!

[N7GTX]

Hedgehopper said:

Do these calipers have larger pistons than the normal 887/888 mod?

Edited by Hedgehopper on Friday 28th August 13:25

The piston in each caliper is 57mm diameter if that helps.

Edited by N7GTX on Friday 28th August 15:43

[N7GTX]

BoostedChim said:

It does sound like a bigger and cheap alternative to 888/887 calipers. I would check those bolt are high tensile, £2 sounds a bit cheap for them. Ideally you need 12.9 or 10.9 not the standard 8.8 most bolts are, it'll be stamped on the bolt head. Personally I would put a set of 16" on the front as well, thats a bit too closer for my liking. If you hit a pothole and it buckles the wheel, that gap would lock the wheel up.

Main post now amended!
The plated screws shown in the picture were used for setting up and measuring only as I had them in my van. The ones I have used on the actual fit are M12 x 45mm socket head, high tensile 12.9 screws as you recommend!. They cost £2.50 for 4 to be exact (not £2) and from Kay's Fasteners (now called Kay Fast) in Ossett next to where I live. They do mail order mainly. Very helpful and knowledgeable people.

I was concerned about the clearance but it is just at the corner of the caliper where it meets the smaller diameter part of the wheel. I have now ordered some 5 mm wheel spacers which should give sufficient clearance. As the pads wear down then this will help too.

Edited by N7GTX on Friday 28th August 15:37

[N7GTX]

Barreti said:

Great work Iain.
If you don't mind I'll pinch all the details for the Griffith Alternative Parts List - which is a bit of a misnomer because I love recording stuff like this for posterity.

You're from Ossett? My home town and my mum and two brothers still live on Bankfield Close, Dimple Wells Rd and Headlands respectively.
Where abouts are you?

Help yourself! I need to look at the rears next. Seen another thread with the current larger vented set up but might do some wandering in my favourite scrpayard. You never know....
I'm in Horbury, opposite the Victoria pub on Westfield Road/Victoria Street junction.

Glad you men like it, its so much better with pictures. Thanx

Edited by N7GTX on Friday 28th August 23:30

[N7GTX]

QBee said:

N7GTX mentions doing the rears next. Did he do them? What did he use?

I found that fitting ventilated grooved 273mm (ie standard sized) Black Diamond disks and decent pads (I used DS2500 Ferodo) gave my rear brakes plenty of stopping power even on track.
They are combined with 324mm fronts with grooved disks (Black Diamond again - Focus RS), 4 pot callipers and Hawk pads.
And yes, I do run 17 inch wheels all round.

Not yet QBee. Should really have done them while overhauling the suspension bushes.

You lot keep spending my money...

[N7GTX]

s3c chris said:

Hi all.

This is a very interesting thread and seems a relatively easy way of upgrading the brakes.
For your information, I am pretty sure that Jaguar X type calipers are the same as the Mondeos and "Big Red" of Worcester sell rebuilt calipers in lots of pretty colours too!

Just out of curiosity, having only had experience of the 260mm standard discs, Is the stopping power significantly increased? I would assume so.....

Thanks for posting this.

Regards Chris.

You are correct, X-type calipers are the same as Mondeo Mk3s (almost the same cars underneath) but the reason for choosing Mondeo ones was their cheapness and availability.

There is not a big increase in stopping power, but you can tell when approaching a roundabout too fast.

If you want big braking then you need 4 or even 6 pot calipers. The Mondeo/X-type are 2 pot ( 2 pistons) albeit the pistons are 60mm in diameter. I also took the view that if Ford considered that 300mm discs were good enough for their ST170 which weighs more than a Chim, then they would be perfectly okay.

Despite QBee's comments about bragging rights, I did mine because the insurance company asked if the brakes had been increased following the turbo upgrade and this was the cheapest and easiest solution for me.

[N7GTX]

QBee said:

N7GTX said:

Despite QBee's comments about bragging rights, I did mine because the insurance company asked if the brakes had been increased following the turbo upgrade and this was the cheapest and easiest solution for me.

Not aimed in your direction. You had made that perfectly clear at the start of this thread - with the turbo you clearly needed a brake upgrade. I completely agree, as you wouldn't have done the turbo upgrade just for the sake of it.
But you probably wouldn't be surprised at the number of cars are only ever driven to car shows on a summer Sunday that have had serious sums spent on mechanical upgrades.

Absolutely correct and these brakes were done on the cheap (relatively speaking) - you know; a Jock in Yorkshire and all that....

[N7GTX]

QBee said:

N7GTX mentions doing the rears next. Did he do them? What did he use?

I'm on with it now QBee. Aiming to fit 280mm rear discs. Some adjustments need to be made so once I have worked it out I'll post up a 'how to'.

[N7GTX]

QBee said:

N7GTX said:

QBee said:

N7GTX mentions doing the rears next. Did he do them? What did he use?

I'm on with it now QBee. Aiming to fit 280mm rear discs. Some adjustments need to be made so once I have worked it out I'll post up a 'how to'.

I have to ask "why?".
But I do have to ask if you are on the earlier rear disks or the later 273mm ones?
If the latter, then Shirley you just need to upgrade your pads, or pads and disks?
My rears work fine with 273mm grooved ventilated disks and DS2500 pads, so I felt no need to change callipers.
My fronts are similar disks and pads, but 324mm, with 4 pot callipers, and the whole set up still feels balanced.

My rear discs are 253mm and were on the car when I got it. The surface area covered by the pads is really quite small. And aesthetically, they look absolutely silly next to the 300 fronts . As I am on standard 15" wheels I cannot go any bigger than 300mm as you have done so my aim was to have the biggest that would fit without huge expense of new wheels/tyres/4 pots/vented etc etc.

So, I have spent hours in the scrapyard 'borrowing' parts to see how it all fits together. I had a trial fit today and I think its all but there now.
I am using 280mm Focus ST170 rear discs as they are 4 stud fitting. The caliper mounting is a Ford Mondeo Mk3 which fits directly to the existing TVR hub bracket with no alterations. I also used the calipers from the same car and it will take standard Mondeo pads.
The original mounting bracket bolts are too long and, as the top one does not come out unless you unbolt the hub from the housing, I will cut it off and then fit the original Mondeo ones which are shorter.
On the trial fit the inside clearance between the disc and the mounting bracket was too tight (0.5mm approx) so I used a 5mm wheel spacer, fitting it to the hub then the disc. This has centred the disc in the bracket.
That just leaves the handbrake assembly to sort. The TVR comes up from underneath and the Mondeo one operates from the front of the car. I have now sorted that and it only takes 5 mins and no special tools. It is hard to explain without pics so I have taken lots for the final 'how to'.
Hopefully next week after Chatsworth I should be able to complete it. It should keep Daz happy as it is another budget upgrade

[N7GTX]

BoostedChim said:

N7GTX said:

I'm on with it now QBee. Aiming to fit 280mm rear discs. Some adjustments need to be made so once I have worked it out I'll post up a 'how to'.

Are you looking at the later Ford Mondeo rear brakes? I had a quick look and was surprised they used solid discs. I suppose that rears don't get that hot so its just extra weight

Early Mk3 Mondeo caliper and bracket with ST170 (2002 era) discs, just like the fronts really. I am on 4 stud so Mondeo and C-Max are no good.

[N7GTX]

My 253 hiding behind the wheel...

[N7GTX]

s3c chris said:

Hi.

Apologies for the thread resurrection......

I am just wondering how this brake upgrade has been performing since it was done?
I have been looking at the 283 mm conversion in the classifieds and wondering if there was an advantage with that system as opposed to this Ford based one.

Also, these calipers will obviosly just fit behind 15" Imola wheels, has anyone tried this with the 15" Estoril wheels?

Many thanks, Chris.

The brakes have been good. Passed the MOT last week with some decent figures. You will need wheel spacers if you do this upgrade as the caliper just touches (only just on one side but clears on the other), especially when things get hot. I did this for insurance purposes after the turbo was fitted. Brembo and other upgrades have more powerful calipers with 2 or 4 or more pistons.
I did the upgrade partly for cosmetic reasons as the original discs seemed tiny behind the wheels. I also upgraded the rears using Mondeo calipers and Focus ST discs mainly to fill the hole behind the wheels. The Mondeo rear calipers have actually given me a proper working handbrake that even holds on a hill.