Register Login
Shop4Parts - UK's largest online superstore for FIAT and Alfa Romeo parts
Comment
 
Guide Tools Search this Guide
<!-- google_ad_section_start -->Rear disc brake conversion II<!-- google_ad_section_end -->
Rear disc brake conversion II
or how i've done it :)
Published by nmrmak
14-12-2008
Unrated

User Rated:Unrated

Show Printable Version  Email this Page 
Rear disc brake conversion II

Okay, this will be a short compilation of information i dug up when i did my rear disc brake conversion. This is merely a guide that should point you in the right direction, and explains how i did the conversion myself, so use it as a list of pointers, not as an official service procedure manual. I don't guarantee the procedures here are safe, that they won't destroy your car, kill you, burn your car or anything like that. Always pay attention to what you do and use common sense, you're dealing with the brakes here, and they are the most important part of the car because they stop you before you go into that tree. Read this guide and use these informations at your own risk and responsibility. Always triple check the parts before you buy them and don't blame me if you buy the wrong parts. If you have the slightest doubt you can do this, then don't do this. If you see i said something wrong in here, please report it to me so i can fix it.

You should see this as just another online resource that could help you, but could harm you if anything written in it is wrong. Act accordingly.


First off, you'll need to set aside a lot of time for preparations and research. Once you have all the needed parts, you will be looking at one to a few days labour if you're doing it yourself with the appropriate tools, depending on the skills and experience you have and some other factors such as luck

As far as parts are concerned, i'll try to break it down into several categories:

- Calipers

Click image for larger version

Name:	resize-img_0041.jpg
Views:	921
Size:	287.0 KB
ID:	54910
I did my conversion using two rear calipers that the breaker told me came off a uno turbo, but apparently came from a Marea. To the best of my knowledge, you could use calipers from:
Marea 2.0 or 2.4TD
Tipo 2.0
Tempra 2.0
Alfa 155 1.8

The important thing to note is that you will need REAR calipers. In theory, front calipers could be used, but they don't have a handbrake mechanism, so you will need rear ones.

Once you source the calipers, they might need some repairs/refurbishing (unless you bought refurbed or new calipers). Basically, the only thing that must be preserved in the caliper is the brake piston. If it has any deep scratches (ESPECIALLY if the scratches run down the length of the caliper), you're boned, and you'll probably need to buy another piston (rare to find) or buy an another caliper and hope you have more luck with it.
example of a "totaled" piston:
Click image for larger version

Name:	resize-brake_piston.jpg
Views:	412
Size:	129.6 KB
ID:	54909
If repairing them yourself, you should replace all the rubber ring things, and it can take a few days to find those parts and carry out the repairs.

- Mounting plates
You will need a way to mount the calipers to the car. So, you should go out and buy a uno turbo mounting plate. If you can't find it (my case ), you'll have to make your own. I'll include the "technical" drawing here for reference. You can use it to order water-cut plates like i did or go for some other cutting technique. Mine were 6mm thick and work allright. Sorry for the non-english version, but "Specifikacija otvora" means drilling positions, and "Poluprecnik" means radius. That was pretty much all that the water-cut guys needed from me
Click image for larger version

Name:	sei_anker_platna.jpg
Views:	2270
Size:	83.3 KB
ID:	54918Click image for larger version

Name:	gotove_anker_ploce.jpg
Views:	758
Size:	64.7 KB
ID:	54917
- Brake pads
Order original uno turbo pads or go aftermarket

- Brake discs
You'll need original uno turbo rear disks or equivalent. These are 227mm in diameter and fit a range of fiat cars, you shouldn't have a problem sourcing those.

- Brake hoses
I've had those custom made for me. You should take your own measurements, but just for reference, mine were 45cm in length, male connectors on both ends.

- Bolts

Well, the bolts you'll need are M10, but you should go for shorter ones, i think 25mm length would be fine with a washer. You'll need 4 of those, 2 for each side. The bolts that keep the mounting plate to the car are already there, holding the drum. You can reuse those on your mounting plate. The bolts should be long enough to go through both the mounting plate and the caliper, but not all the way through (or else it will contact the disk). Would be best to find a bolt that's exactly the length of width of mounting plate + width of the flat mounting part of the caliper. In reality, you'll need a longer screw and a washer probably.

- Hubs
I used uno turbo hubs instead of the cento hubs. If you go for cento hubs, you'll need a spacer, but i didn't go that route so i can't help you much. UT hubs are a bolt on replacement.

- Handbrake cable
This is something i still haven't solved, but it shouldn't be a hard task. I reused the sei cable, but cut around 5-10cm of the cable guide (leaving the cable inside intact) so the cable guide is a little shorter. An alternative would be to ask for a seicento handbrake cable, just 5-10 cm longer.


The procedure outlined:

Jack up the car, put it (the side you'll be working on) on an axle stand or something similar, remove the wheel. undo the 2 bolts keeping the drum in place (and keep them, you'll need them later), remove the drum.
Under it you'll see the drum brake mechanism and the hub. Undo the hub nut (you'll need a 30mm hub tool for that) - these are very tight so pay attention, you don't want to injure yourself...make sure the axle stand is stable enough (i used large chunks of wood so my support was rock solid, but if you think your axle stand won't be up to the task, try loosening the nut a little with the car on the ground and the wheel on and finish the job with the car on the stand). Many people recommend that you always use new hub nuts. You could reuse it on your own responsibility, but you should definitely reuse the small washer that sits between it and the hub. Remove the hub carefully. Best way is to reach with your hand behind it and find where it sits on the small axle thing and push on that so you don't damage the bearings. Remove 3 of the 4 bolts that bolt the drum mechanism to the car and keep them (you will reuse them in about 10 minutes).
Drum, hub and 3 bolts removed:
Click image for larger version

Name:	resize_dobos1.jpg
Views:	1058
Size:	154.5 KB
ID:	54912
Remove the handbrake cable from the drum mechanism. What i did in my case was remove the part of the brake line that is on the rear suspension arm. Disconnect it and remove the last bolt keeping the drum mechanism, then remove the drum mechanism from the car.
Drum mechanism and slave brake cylinder removed:
Click image for larger version

Name:	resize_drum_off.jpg
Views:	626
Size:	147.4 KB
ID:	54913
(Warning: brake fluid leaks from the system at this time, you might want to catch it into some sort of a container and dispose of it when you're done). Bolt on the mounting plate where the drum mechanism used to be using the 4 bolts you just recovered.
Mounting plate bolted:
Click image for larger version

Name:	resize_mount_plate_on.jpg
Views:	724
Size:	119.6 KB
ID:	54916
Put some grease on the short axle thingy and put the UT hub on. You should ask someone more experienced if you've never replaced a hub before. Re-use the washer you removed when you removed your old hub and tighten it using a new hub nut. It will take a lot of force to tighten it, again, consult someone more experienced to tell you just how tight to go.
New hub on:
Click image for larger version

Name:	resize_hub_on.jpg
Views:	675
Size:	138.6 KB
ID:	54915
When the new hub is on, put the new disk over the hub and secure it using the two smaller screws you recovered when you removed the drum. (TIP: before you screw in the smaller two screws, first screw in 2 wheel bolts to help you center the disk. Tighten them real good, screw in those 2 smaller screws, then undo the wheel bolts.)

Now for the hydraulics. (you can do this part first so the brake fluid doesn't leak all the time after removing the drum) Since i had brake hoses with two male connectors, i had to first screw in the hose into the caliper, and then screw the other part into the rest of the brake system, while rotating the caliper (the caliper was actually hanging off the hose in the process).
Pic:
Click image for larger version

Name:	resize_hanging_caliper.jpg
Views:	818
Size:	166.0 KB
ID:	54914
After you do that, make sure the piston is in the fully retracted position. If it isn't, use a piston compressing tool (which you don't have, so you'll have to lightly hammer it in with the aid of an extension like i did or use a crimp ). Put in the brake pads and then position the caliper on the disk, over the mounting plate, and screw in the upper bolt so that the caliper can rotate around it (don't tighten it completely). Bleed the system with the calipers rotated at such an angle so that the bleeding valve sits at the highest position. Bolt in the lower screw after you do it. Use washers if the screws are too long and contact the disk on the other side.
Click image for larger version

Name:	resize_disk_final.jpg
Views:	1062
Size:	149.8 KB
ID:	54911

As far as the handbrake goes: my handbrake cable was too short (some people suggest that you can in fact use the cable already on the car, but i'd go and buy a cable that's 5-10cm longer than the factory made one). The temporary solution i had was to cut a part of the metal cable guide and that did the trick. You should cut the hoops on the cable ends so they can pass through the mounting hole in the caliper and run them to the handbrake mechanism on the caliper. You might need to play with the handbrake adjustment screw, but i think there is already a guide on how to that.

Re-fit the wheel, lower the car to the ground and test the brakes at low speeds first, and see that your handbrake works before going for a street test. Use common sense and be very careful. If possible, find a long stretch of asphalt with no traffic on it (i used a deserted road where there's nobody around) and bed in the brakes, and test them with high speed braking after the disks and pads are bed in. You want to be sure you can stop the car from 100kmph before going any faster than that. Be careful, the car might oversteer if you upgraded only the rear brakes (but it didn't in my case).

Excuse my English, it's not my native language, so i might have messed up some tech terms.
Have fun and before you actually do any of this, go back and read the introductory warning
Thanks andybdrinkell, blu73, goona, custard thanked for this post
Likes andybdrinkell liked this post
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

Old 22-02-2009   #1
Join Date: Feb 2009
Location: St Helens
Posts: 241
Thanks: 1
Trader Rating: 0
United Kingdom 
Re: Rear disc brake conversion II

When you say you can use cento hubs, do you mean cento rear hubs? I.e. putting back on the ones you take off? I suspect they're the same but are Sei hubs the same as Cento hubs for this?
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

Renrut is offline Reply With Quote Quote 
Old 23-02-2009   #2
Join Date: Aug 2007
Posts: 547
Thanks: 12
Trader Rating: 0
Serbia 
Re: Rear disc brake conversion II

By "cento", i meant seicento there. As i said, i used a uno turbo hub, which is a few mm wider, so the disk is centered within the caliper. If using a seicento hub, you have to have a spacer made up between the hub and the disk (as far as i know), but i didn't do it that way, so i have no experience with it. I'm sure someone mentioned it in one of the brake conversion threads, so it might be good to search around the forum for more info. This guide is just one way to do things, you always have alternatives.
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

nmrmak is offline Reply With Quote Quote 
Old 24-02-2009   #3
Join Date: Feb 2009
Location: St Helens
Posts: 241
Thanks: 1
Trader Rating: 0
United Kingdom 
Re: Rear disc brake conversion II

Thanks. I'll have a dig around some more. I think I'd rather go with the newer 240mm calipers/discs if I can and retain the seicento hub.
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

Renrut is offline Reply With Quote Quote 
Old 02-03-2009   #4
Join Date: Sep 2005
Location: Johannesburg
Posts: 17
Thanks: 0
Trader Rating: 0
South Africa 
Re: Rear disc brake conversion II

WOW this is great thank you so much for all the information. The plate was my main concern cause I did not want to strip the whole assembly to get he mounting plate details.
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

ECL is offline Reply With Quote Quote 
Old 20-04-2009   #5
yellow pocket rocket
Join Date: Apr 2007
Location: Romford
Posts: 15
Thanks: 0
Trader Rating: 0
rick.jones has donated!
United Kingdom 
Re: Rear disc brake conversion II

dear sir, i have read your "how to install rear discs to a cento" and there is no mention about difficulty in brake pressurising.

i installed my GT front discs and uno turbo rear discs about 1 year ago adn then had trouble bleeding the brakes to get the pressure.
the car was sent away as i am having a track engine fitted (another story) and the engineer said it may be the ABS unit not working.

i have just had a call from him, all the ABS has now been removed and the brakes will still not pressurize.

the front brakes are ok, but the rear brakes do not move. after several pumps the pedal goes fairly hard but does not remain with the pressure.


all the parts i used were brand new or reconditioned.

any ideas, i have read somewhere that the master cylinder is not big enough to cope with the additional fluid?????

help!!!!!!!!!!!!!!!!!!!!
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

rick.jones is offline Reply With Quote Quote 
Old 29-04-2009   #6
Join Date: Aug 2007
Posts: 547
Thanks: 12
Trader Rating: 0
Serbia 
Re: Rear disc brake conversion II

I sent you an email.

Basically said that if the brakes feel mushy and you bled them properly, it's probably an internal MBC leak.
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

nmrmak is offline Reply With Quote Quote 
Old 10-08-2009   #7
yellow pocket rocket
Join Date: Apr 2007
Location: Romford
Posts: 15
Thanks: 0
Trader Rating: 0
rick.jones has donated!
United Kingdom 
Re: Rear disc brake conversion II

i never received the email from you, hmmmmmmmm strange. what do you mean by MBC leak, it is a new one. i have been told that the seicento MBC is not man enough and i need a larger capacity. do you know of one that will fit?

Rick
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

rick.jones is offline Reply With Quote Quote 
Old 10-08-2009   #8
Status: DEFCON Grumpy
 
custard's Avatar
Join Date: Nov 2003
Location: Edinburgh
Posts: 30,129
Thanks: 496
Trader Rating: 1
custard has donated!
United Kingdom 
Re: Rear disc brake conversion II

Quote Originally Posted by rick.jones View Post
i never received the email from you, hmmmmmmmm strange. what do you mean by MBC leak, it is a new one. i have been told that the seicento MBC is not man enough and i need a larger capacity. do you know of one that will fit?

Rick
post questions in the main cento forum and they will get a faster response
custard is offline Reply With Quote Quote 
Old 25-10-2009   #9
Join Date: Feb 2009
Location: S\Wales
Posts: 5
Thanks: 0
Trader Rating: 0
United Kingdom 
Re: Rear disc brake conversion II

Hi, excellent guide.
How did you go about the handbrake cable and mounting (handbrake cable on lower side of callipers and mount on high side of radius arm). cheers
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

Wolfman is offline Reply With Quote Quote 
Old 31-10-2009   #10
Join Date: Aug 2007
Posts: 547
Thanks: 12
Trader Rating: 0
Serbia 
Re: Rear disc brake conversion II

Thank you!

First the cable was relocated under the arm. Then I used plastic tie straps to hold the handbrake cable under the arm with the car on the ground (weight on the suspension). When the car is jacked up, the cables have some slack between them and the arm (maybe 1-2cm, not more).

The handbrake cable was custom made because i found that the existing sei handbrake cable was too short for the application.
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

nmrmak is offline Reply With Quote Quote 
Old 06-05-2010   #11
Join Date: Oct 2007
Posts: 3,047
Thanks: 128
Trader Rating: 0
United Kingdom 
Re: Rear disc brake conversion II

standard sei ones can be long enough as mine and a few other conversions ive done have been, to make one fit cut the spring and the white plastic bush off and grind the hoop on the end to a square shape so it can fit through the loop on the back of the calliper and hook it on. worked every time ive done it, just for people looking in the future.
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

clock34 is offline Reply With Quote Quote 
Old 13-06-2010   #12
Join Date: Jun 2010
Location: Malta
Posts: 1
Thanks: 0
Trader Rating: 0
Malta 
Re: Rear disc brake conversion II

when u say UT hubs u mean stock UT rear hubs right ? the uno fire hubs dont fit ?
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

Neil gt1 is offline Reply With Quote Quote 
Old 14-07-2010   #13
Join Date: Dec 2009
Posts: 1
Thanks: 0
Trader Rating: 0
Poland 
Unhappy Re: Rear disc brake conversion II

Hi to everybody. Sorry for my poor english

I've 1 question- What about hand brake? I bought rear caliper from AR 146 and affraid that I cant used oryginal brake cable.
Any ideas?
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

JaRabbit is offline Reply With Quote Quote 
Old 30-03-2011   #14
Join Date: Aug 2007
Posts: 547
Thanks: 12
Trader Rating: 0
Serbia 
Re: Rear disc brake conversion II

Sorry for the late reply, hopefully someone else might benefit from this... Yes, i mean the stock UT rear hubs.

As for the handbrake cable, you can get one manufactured, you'll just have to measure the length.
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

nmrmak is offline Reply With Quote Quote 
Comment
Currently Active Users Viewing This Guide: 1 (0 members and 1 guests)
 
Guide Tools Search this Guide
Search this Guide:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump
Similar Threads
Guide Guide Starter Category Comments Last Post
(T) Rear disc conversion arc Cinquecento / Seicento 206 16-08-2008 14:02
(G) Hoses for rear disc conversion! Andi1985 Cinquecento / Seicento 4 19-09-2007 13:24
(T) Rear disc conversion - drawings/fabrication help GoBe Cinquecento / Seicento 21 24-06-2007 20:52
(T) rear disc brake conversion custard Cinquecento / Seicento 0 12-04-2007 17:54
(G) rear disc conversion on my panda. christopher watson Panda (Classic) 30 06-06-2006 21:36