Quantum 2+2 Brakes advise please (and fan switch!)

[Jamest142]

Hiya folks

I am after some advise please?  I am looking to change the rear brake cylinders on Q2-002 as I have a very minor weep issue, I have read both the build manuals, and both state that these are not standard Fiesta parts.  The late build manual says 'change the rear wheel cylinders to the correct size, new ones are supplied in the kit', and the original build manual says '17.5mm for Vented Front discs, and 15mm for solid front discs, this is not the same on any other Fiesta'... 

Does anyone know of the correct parts please, and also are Ferrodo still the brake shoe brand of choice, or is there anything more suitable?  Also I may change the front discs / pads as I am not going anywhere fast (pun intended!), is there anything to look out for on these in terms of brand etc?

Finally - the fan control switch has failed, I have a new one to fit, but no amount of socket work will shift it, and I am heading for causing damage - any recommendations for where and how to fit an new switch to the cooling system, or should i just fit a manual switch on the dashboard?

Hope you are all keeping safe, and best regards

James T

Q2-002

www.bostin.photography

 

[Jim Hearne]

The rear  brake cylinders are from Mk1 / Mk2 Fiesta

 

Possible sizes are:

 

Mk1 Fiesta:

 

15 mm

17.5 mm

19 mm

 

Mk2 Fiesta

 

15 mm

17.5 mm

20.6 mm

 

The bigger sizes are for the XR2

The actual size Quantum recommended changed and it was also different depending on if you fitted the rear bias / inertia valves to limit the rear brake pressure.

The problem is the rear of the 2+2 is a lot lighter than the rear of a Mk1 or Mk2 Fiesta and the rear wheels can lock under heavy braking which isn’t a good thing.

I seem to remember i was asked when i bought my kit what my car spec was and if i was using the rear bias valves and Quantum supplied the correct size.

 

If you’ve had no problems with the rear brakes then i would refit whatever size is on there.

If you take the drum off and pull the rubber back you should be able to measure the bore dia with some calipers without having the remove anything else.

 

 

If you have a gas torch or hot air gun then get the engine hot, drain some of the coolant off (carefully) and then heat the switch as much as you can.

This may free it off.

Otherwise, you will have to fit one in the top hose, you can buy adaptors from the kit car parts suppliers, a tube with a boss in to take a switch.

 

If you manage to get the switch out or fit a different one then make sure you replace the connector.

As soon as the connector or switch contacts overheat they damage the other half, replacing the switch with a overheated connector will just result in the connection overheating again and needing another new switch.

Ideally the fan should be switched via a relay.

Interestingly while sorting out a early Mk1 Fiesta loom for 003 i found there was a factory fitted relay on the fan, something they must have dropped later to save a few pennys.

 

Jim

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[Jim Hearne]

Links to the brake cylinder details.

 

Mk1 https://ford.catalogs-parts.com/#{client:1;page:part;lang:en;category:car;catalog:4;param:no;group:0;groupsubgroup:1517;subgroup:15136;subsubgroup:65638}

Mk2 https://ford.catalogs-parts.com/#{client:1;page:part;lang:en;category:car;catalog:4;param:no;group:0;groupsubgroup:1517;subgroup:15136;subsubgroup:65639}

 

Jim

 

 

From: 'Jamest142' via Quantum Owners Group

Sent: Monday, April 6, 2020 1:42 PM

To: Quantum Owners Group

Subject: [Quantum Owners] Quantum 2+2 Brakes advise please (and fan switch!)

 

[kynastonp .]

Jim is correct ,the early saloons did not fit the rear limiting valves and quantum specified the smaller rear cylinders to balance out the brakes. Over time some cars were fitted with the larger cylinders when maintenance was done and this caused problems to owners. The factory sent out a warning notice to owners about this . They then modified the cars to take the limiting valve ,marked the location on the body and included the instructions on how to modify the valve bracket .

Sent from Outlook Mobile

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From: quantu...@googlegroups.com <quantu...@googlegroups.com> on behalf of Jim Hearne <j...@quantums.info>
Sent: Monday, April 6, 2020 2:42:38 PM
To: quantu...@googlegroups.com <quantu...@googlegroups.com>
Subject: Re: [Quantum Owners] Quantum 2+2 Brakes advise please (and fan switch!)

 

To view this discussion on the web visit https://groups.google.com/d/msgid/quantumowners/1D09E9402EB94EE2B3843E42C00C8DBC%40JimQuad.

[susanandmartin]

I finally managed to open the parts file I had (I wish Microsoft wouldn’t change things when I get a different computer!

My car is a saloon, and may not be the same as the 2+2 due to weight distribution.

It uses 15mm ones, which are Diesel Fiesta. Part number is off my list, which from the RH column suggests all Fiestas except XR2 are 17.5mm

 

Rear Brake Cylinder

84FB

2261

AC

1630359

Fiesta Diesel 1.6 part 15mm Dia (XR2 is 20mm- others 17.5)

 

I got another pair (a5mm diesel)  off ebay last year because mine seized up (lack of use!)

My car passed SVA with this set -up (It has the G valves near wheelarch)

My best suggestion is to pop a cylinder out of yours and measure it with Vernier to find diameter and buy the same.

Hope that makes sense, Martin Scott

 

Sent from Mail for Windows 10

 

From: 'Jamest142' via Quantum Owners Group
Sent: 06 April 2020 13:42
To: Quantum Owners Group
Subject: [Quantum Owners] Quantum 2+2 Brakes advise please (and fan switch!)

 

Hiya folks

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[Jamest142]

Hi

Many thanks for your assistance as always, should keep me occupied and out of mischief, or an excuse *not* to have to tidy the loft out.

I will be making an electronic fan switch, found some parts I purchased 25 odd years ago, knew they would be useful sometime :)

Best regards

James T

Q2-002

www.bostin.photography

[Dave English]

Hi James.

I know your car is a 1600 so I'm guessing it's XR2 based with vented discs. My early build manual for the 2+2 says to use 17.5mm cylinders (OE number 1630360). These would normally be fitted to non-XR2 Fiestas with rear brake compensators.

The 2+2 manual also says to use the rear compensators with these cylinders. As I started building mine before the manual came out and was working from the Saloon manual, I never fitted the compensators but I still use the 17.5mm cylinders.

So, if you've vented discs at the front, use 17.5mm cylinders at the back, with or without the rear compensators.

As far as I'm aware Ferrodo are still fine, I usually get my brakes from Halfords or Exhausts Unlimited and haven't had any problems.

Discs - a quick look on E-bay came up with Mintex and QH discs for less than £30 a pair and Burton Power do a pair for £36 + postage.

As for the switch problem, sorry, I can't help. I have a 24" 'Breaker' bar and a single hex, double depth socket, so when I changed my switch, it didn't resist for long!

For it's replacement, look for a switch with a 103-98 degree range (or there about). I fitted the (supposedly also correct) 95-88 one and it's too low with an 88 degree thermostat.

Regards

Dave English

Q2-009

[Derek Clews]

HI James,

Don’t know if this will help, but I ended up fitting a 102/93C Cambiare VE7096. fan switch in the standard housing for varying reasons.  Not least running out of time for re-mot’ing the car and having it in my hand!  That one has a slightly different range than most, but I find it works well as it takes the temp down a noticeable amount before switching off again compared to the often quoted 103/98C ones.  I also found that ebay suppliers frequently miss-represent the connectors and this one had two standard spades, which is easy to DIY replace getting rid of the old ford connector.  There seem to a number of different ones that fit the housing and thread, so there is a lot of choice.  I also went for the simple approach and just made a short jumper cable to add to the car kit if I wanted to manually switch it on in future if there was a switch failure.  But will probably never have one again!

Keep well

Derek

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IMPORTANT NOTE: All information presented herewith is provided on an "As Is" basis, without warranty or the implication thereof. Neither the Quantum Owners Club nor the individuals associated with the Quantum Owners Club or in the preparation of the above information shall have any liability to any person or entity with respect to liability, loss, or damage caused or alleged to be caused directly or indirectly by the instructions contained within this or related message(s).
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[susanandmartin]

I don’t know for certain, but given my experience of QH parts, their quality isn’t what it used to be. I fitted a genuine QH track control arm to my Rickman Ranger, and it had terrible play within less than 2000 miles – It was worse than the other side which was probably original, but certainly over 11 years old because I’d never changed it. The vendor (a respected classic parts dealer) confirmed the part was from a genuine source, and refunded me. I bought ‘first line’ ones (available from local motor factor) and they have been ok so far (about 5k miles). I recently bought new Ferodo discs and pads (via Germany) for my Wife’s Ford Ka+, as I didn’t want to buy an unknown brand. Doing some research, it appears Ferodo are still a UK, family-owned company!

Martin Scott

 

Sent from Mail for Windows 10

 

From: Dave English
Sent: 07 April 2020 11:22
To: Quantum Owners Group

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[Jamest142]

Hi Dave & Derek

Many thanks for the suggestions / information.  I have ordered Mintex front pads and rear shoes, I have also cheated, and ordered both 15mm and 17.5mm cylinders, so I should hopefully have the right ones.

With regards to the switch, it seems to be so tight I am in danger of either stripping the threads, or cracking the housing, so I am going with a home brew resolution - I've found some thermostat ICs (Dallas DS1620) which can be programmed to switch a relay on and off at set temperatures with hysteresis.  I even found a laptop with a parallel port to use the programmer I made back in 1997...  will take a bit of trial and error, but I've got a bit of time on my hands to have a play.

Keep safe, and thanks to you all for your help.

Best regards

James T

Q2-002

www.bostin.photography

[Jamest142]

Hi folks

Many thanks for all the suggestions and help as always, I have had the new brakes fitted, the cylinders were not weeping, they were proper leaking, and the units fitted were 15mm bore.  Also needed new rear flexi pipes as the originals were welded to the pipes...

Also finally fitted and tested the electronic fan temperature switch, fully programmable, so have set for turning on at 102C, then off at 92C.  My mechanic agreed that the original switch would either strip the threads, or crack the casing, so it is not going anywhere...

Have fun and keep safe.

James T

Q2-002

www.bostin.photography