A rear wheel cylinder question !!

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h11poc
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Joined: Sun May 16, 2021 6:37 pm
fill in the right answer: 15

A rear wheel cylinder question !!

Post by h11poc » Wed Oct 06, 2021 3:06 pm

Hi all.. What size do I need for the 1991 GTii rear wheel cynlinder. The one I took off was the "two bolt hole" 14mm one but I am confused as to whether this was right. The rear brakes were lousy.



mark1gls
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Location: Somerset

Re: A rear wheel cylinder question !!

Post by mark1gls » Wed Oct 06, 2021 9:43 pm

If you have the 2 little valves underneath the master brake cylinder then you should have the 17mm rear brake wheel cylinders.
The 2 valves reduced the pressure so you need the bigger brake cylinders.

Both sizes, 14mm and 17mm have the same fixings.

https://www.eurocarparts.com/p/pagid-wh ... -134440148


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323

h11poc
Posts: 78
Joined: Sun May 16, 2021 6:37 pm
fill in the right answer: 15

Re: A rear wheel cylinder question !!

Post by h11poc » Thu Oct 07, 2021 10:37 am

Thanks for that. I did have the two regulators under the master cylinder so bought two cylinders from your link. The big bonus was there is an offer on those cylinders so they were just over a tenner each instead of 16.

P



mark1gls
Posts: 3658
Joined: Thu Apr 02, 2009 9:28 pm
fill in the right answer: 10
Location: Somerset

Re: A rear wheel cylinder question !!

Post by mark1gls » Thu Oct 07, 2021 9:50 pm

Good luck undoing the bolts which hold the cylinders in place, make sure you clean out all the dirt from inside the Allen key head and tap the Allen key into the bolt.
When fitting the new cylinder coat the bolt threads in copper grease as it will help next time you change the cylinders.

There is always an offer at Euro car parts online, so make sense to click and collect or delivery as it’s cheaper than just walking into the store…


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323

mark1gls
Posts: 3658
Joined: Thu Apr 02, 2009 9:28 pm
fill in the right answer: 10
Location: Somerset

Re: A rear wheel cylinder question !!

Post by mark1gls » Thu Oct 07, 2021 9:52 pm

If your brake fluid is more than 5 years old bleed new fluid through the system as it makes a world of difference.


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323

h11poc
Posts: 78
Joined: Sun May 16, 2021 6:37 pm
fill in the right answer: 15

Re: A rear wheel cylinder question !!

Post by h11poc » Fri Oct 08, 2021 3:01 pm

:-) 2 litres of castrol brake fluid dot 4 acquired two days ago